149 
64 
py 1 





Copyright ]J^._ 



COPYRIGHT DEPOSIT. 



CHEMISTRY 
OF THE HOUSEHOLD 



BY 

MARGARET E. DODD, S. B. 

GRADUATE OF MASSACHUSETTS INSTITUTE OF TECHNOLOGY 
TEACHER OF SCIENCE, WOODARD INSTITUTE 




CHICAGO 
AMERICAN SCHOOL OF HOME ECONOMICS 

1910 



A ^ 









COPYRIGHT, 1904, 1905, BY 
AMERICAN SCHOOL OP HOUSEHOLD ECONOMICS 

COPYRIGHT, 1907, 1910, BY 
HOM£ ECONOMICS ASSOCIATION 



CCI,A^61873 



CONTENTS 





Page 


Water 


I 


The Atmosphere ...... 


. 14 


Combustion ....... 


20 


Fuels . . . . . ' , 


. 23 


Food ........ 


29 


Sugars and Starches ..... 


. 32 


Digestion ....... 


35 


Cooking . • . 


' 37 


Fats 


43 


Nitrogenous Foods 


. 45 


Cooking of Nitrogenous Food Stuffs 


48 


Effects of Cooking ..... 


. 51 


Mineral Matter ...... 


52 


T)ecay ........ 


. 54 


Cleaning . ..... 


55 


Chemistry of the Laundry .... 


. 66 


Removal of Stains ...... 


73 


Bleaching . . . . . 


. 80 


Cleaning AA^oodwork « . . . . 


84 


Cleaning Metals ...... 


. 85 


Chemistry OF Baking Powder . . . 


89 


Lighting ....... 


. 92 


Lime ....... 


102 


Chemistry and Electricity .... 


. 105 


Plant Life ....... 


108 


Chemical Terms, ...... 


. Ill 


The Housekeeper's Laboratory 


113 


Impurities in Water ..... 


. 127 


Laundry Work ...... 


129 



111 



IV 



CONTENTS 



Bluing ..... 
Home Soap Making 
Dishwashing .... 
Latent Heat .... 
Use of the Thermometer 
Bread Making .... 
Home Made Baking Powder . 
Distillation . . . . 

Composition of Gas 
Spontaneous Combustion 
Conservation of Energy 
Bibliography .... 
Program of Supplemental Study 
Index ..... 



131 

133 
135 
138 
140 
141 
142 

143 
144 

146 
146 
149 

151 
163 




o 

2 
o 
o 
u 

'Q 

z 
<: 

hj 
w 

o 

H 



X 



z 




w 




X 




C ) 


10 


H 


TD 


•— < 




u 






(-> 


(Tj 


Pi 







ai 


s? 


O 


c 



Pi c« 

s - 



CHEMISTRY OF THE HOUSEHOLD 

A Day's Chemistry 



BEING an outline of the simplest and most evi- 
dent chemical changes suggested by a day's 
work at home and a description of the various chemical 
substances of interest to the housewife. 

WATER 

The morning bath will introduce us agreeably to the 
wonderful chemical substance, water, and with this oc'cun-enc© 
substance we will begin our study of a day's chemistry. 
The water for the house may come from the town sup- 
ply, from wells, cisterns, or springs. It may be 
''surface water," from pond, lake, or stream, or it may 
be "ground water," from wells or deep springs. Cis- 
tern water is, of course, rain water. Water is present 
in many substances where we might not suspect it. 
All living things contain a large percentage of water. 
Of an athlete weighing 150 pounds, all but about 42 
pounds is water. Wood, meat, vegetables, fruit, when 
dried, weigh from 50 to 98 per cent less. Many natural 
and artificial substances owe their crystalline form to 



2 CHEMISTRY OF THE HOUSEHOLD. 

water and when heated, give off this "water of crystal- 
Hzation" and crumble to powder. Common washing 
soda shows this effect, when exposed to the air, and 
soon gives off so much water that its crystalline char- 
acter is lost. 

Katurai All watcr fouud in nature is more or less impure, 
^**®' that is, it contains substances in solution. It dissolves 
air and takes substances from the soil and rocks over 
which it runs. Often it comes in contact with animal 
and vegetable substances and dissolves something from 
them. Near dwellings the water in streams, ponds, 
and wells is very likely to become contaminated. De- 
caying substances give rise to materials easily dissolved 
in water, which may travel for a considerable distance 
under ground, so that the drainage from the house or 
barn is frequently carried to near-by streams or wells, 
making their waters quite unfit to drink. Fig. I. 

The following experiment will illustrate that air is 
dissolved in water. 

Experiment. Place a tumbler of fresh well-water or 
tap-water in a warm place. After a time, bubbles will 
be seen collecting on the sides of the glass. This is 
air which was dissolved in the water. As the water 
grows warm, it cannot hold so much air in solution and 
some of it separates. 

Distilled Most of the impuritics in water are less easily con- 
verted into vapor than the water itself; hence, when 
the water is boiled, they stay behind while the water 
*'boils away". Water from almost any source can be 
made pure and clear by distillation. Distilled water is 



Watet 



WATER. 3 

prepared in an apparatus known as a still. See Fig. 2. 
A still consists of a boiler, A, and a condenser. In 
the condenser, a coil of tube, D, usually made of pure 




FIG. 1. WELL, CONTAMINATED BY HOUSE DRAINAGE. 

tin, is surrounded by cold water which continually 
runs through the apparatus. The steam, admitted at 
the upper end of the coil, is condensed by the low tem- 
perature and distilled water is collected at the lower 



CHEMISTRY OF THE HOUSEHOLD. 



Rain 
Water 



end. In the laboratory, distilled water is often made 
in the glass apparatus shown in Fig. 3. 

Distilled water has a flat taste, because air and other 
dissolved substances which give water its taste have 
been removed. It will again dissolve the air on being 
])oured several times from one vessel into another. 

Rain is water which has been evaporated from the 
surfaces of natural bodies of water, oceans, lakes, 
and from the land, and is practically free from mineral 
matter, but contains dissolved gases. 

The vapor, cooled at the low temperatures of the 
upper levels of air, falls as rain. The first fall of any 




FIG. 2. A STILL. 
A, Gooseneck; B. Boiler; D, Condensing Coil. 



shower is mixed with impurities which have been 
washed from the air. Among these may be carbon 
dioxide, ammonia, and carbon in the form of soot and 
creosote. It is these last impurities which cause the 



WATER. 5 

almost indelible stain left when rain water stands upon 
window-sills or other finished woods. 




Fii 



Makiug Distilled Water in the Laboratory. 



Water is a nearly universal solvent. It dissolves 
more substances and these in larger quantities than any 
other liquid. At a given temperature, water will dis- 
solve only a certain proportion of the various salts 
and other soluble substances. When the water will 
take up no more, the solution is said to be saturated. 
Increasing tlie temperature generally increases the dis- 
solving power of water for solids and liquids. The 
reverse is usually true for gases. 

When a saturated solution of a solid is cooled, crys- 
tals are frequently formed, many having beautiful 
shapes. Examples are shown in Fig. 4. 

Experiiiiciit. In an earthen-ware or enameled dish 
dissolve as much alum as possible in a little boiling 
water. Pour the solution into a shallow dish or sau- 



Solubility 



6 CHEMISTRY OF THE HOUSEHOLD. 

cer, and set it away for a day or more where it will be 
undisturbed. Beautiful, clear, six-sided crystals will 
form in the dish. If strings are hung in the solution, the 
crystals will form upon them. Rock candy crystals 
are made from cane sugar syrup in this way. 

The experiment may be repeated, using washing 
soda instead of alum. 







<! i> 


iv "> 




Effect of 

Water on 

Metals 



FIG. 4. SHAPES OF CRYSTALS. 

Silver, copper, and tin are not perceptibly dissolved 
in pure water, but when combined with acid substances, 
the compounds formed are soluble. These compounds 
of a metal with an acid are called salts. The salts of 
copper, zinc, and lead are poisonous. Copper, brass, 
(an alloy of copper with zinc) tin, solder, and iron 
are metals easily affected by acids, so that cooking 
utensils made of these materials should not be used 
with acid substances like lemon and vinegar. 



WATER. 



Lead pipes are much used in plumbing, and as a 
rule no evil results follow, since ordinary drinking 
water acts under most circumstances only very slight- 
ly upon lead. The pipes are soon coated with a layer 
of carbonate and sulphate of lead, which is insoluble 
and prevents any further action. Water from new 
lead pipes, or pipes not kept constantly full, or from 
a hot-water system in which lead is used, should never 
be used for drinking or cooking because of danger 
from poisoning. Pure distilled water, or rain water, 
affects lead more than ordinary ground water. 

Rain water absorbs more or less carbon dioxide gas 
from the air and soaking into the soil often comes in 
contact with magnesia in the rocks and with limestone. 
Water containing this 

these 



gas will dissolve 
mineral substances mak- 
ing what is known as 
''hard" water, a very dif- 
ferent substance from the 
original rain water 
which is "soft." This 
subject will be dis- 
cussed when the chem- 
istry of the laundry is 
explained. 





ter- 






- 






;^:^i 


W^ 



' (^^ Filtered, watev 



Effect of 
Water 
on Lead 



Hard 
Water 



Layer of qr&vel 

Lay e-r of cK&rco&l 
Latyev- of gravel 



FIG. 5. A WATER FILTER. 



Ordinary water for drinking purposes is often filtered. 
Filtration will remove small particles suspended in the 
water, but has no effect on substances dissolved in it. 

The small charcoal or sand filters will not remove 



Filteringr 



of Water 



8 CHEMISTRY OF THE HOUSEHOLD. 

the minute living forms called micro-organisms or 
germs, some of which are the cause of disease. A filter 
of porous stone or procelain, in which the water filters 
slowly, is more effective. A good filter is shown in 
Figure 5. 

Water which has strained or filtered through several 
feet of earth is often much improved, but the earth 
filter itself may become contaminated after a while and 
more harm than good result. A thick layer of sand 
and rock, however, removes germs effectively, and con- 
sequently water from deep driven wells is safe, 
iiomposition Water was long considered an elementary or simple 

substance, but towards the end of the last century it 
was found to consist of two quite different substances 
so intimately joined together that the identity of each 
is lost. If we pass an electric current through water 
in the proper way, we see a gas rising in bubbles from 
the end of the wire by which the current enters and a 
like appearance at the wire by which the current leaves 
the water. The two gases have evidently come from 
the water and are the substances out of which it is 
made for the water begins to disappear. By placing an 
inverted glass filled with water over each wire, the 
gases are easily collected. See Fig. 6. When one 
bottle is full of gas, the other will be only half full; and 
on decomposing the whole of a given amount of water, 
this proportion holds true. 

If we test these gases, we shall find them quite dif- 
ferent. The bottle which is full contains a gas called 



WATER, 9 

hydrogen. There is evidently twice as much of this by 
volume in water as of the other gas which is called 
oxygen. These two gases were tied together by what 
is known as chemical force, but the electric current 
separated them and gave us an opportunity to make 
the acquaintance of each by itself. We would hardly 
suppose this clear, colorless liquid to be composed of 
such material. On decomposing pure water from any 



rs 



HYDROGEN 




Fig. 6. 



Decomposing Water Into Oxygen and Hy- 
drogen Gas. 



source, the proportion of oxygen to hydrogen is always 
the same, and in fact, all chemical compounds have a 
certain composition which never varies under any con- 
dition. 

The name hydrogen comes from two Greek words, 

meaning water and to produce. Hydrogen is interest^ 

ing as being the lightest common substance. It is an 

invisible gas like air, but unlike air will burn. If a 



Hydrogea 



10 



CHEMISTRY OF THE HOUSEHOLD. 



lighted candle be placed in a bottle of hydrogen, the 
flame will be at once extinguished, though the hydro- 
gen will take fire at the mouth of the bottle. Fig. 7. 
Hydrogen will unite with other substances besides 
oxygen ; that is, it will join with other substances by 
chemical force. It forms a part of most animal and 
vegetable substances. 





Tig. 7. 



Hydrogen Will Burn 
iu Air. 



Fif. 8. A Candle 
Burns Vigorously in 
Oxygen. 



Oxygen Oxygcu, as wcll as hydrogen, is a tasteless, color- 

less, odorless gas. The weight of a given volume is 
sixteen times that of the same volume of hydrogen. 
It is very abundant and the most important substance 
to mankind. Should we test this gas with a, lighted 
candle, as we did the hydrogen, we would find that 
the oxygen would not give a flame, but that the, candle 
would burn far more vigorously. Fig. 8. 



WATER. 



II 



When substances burn in oxygen they really unite 
A^ith it chemically, forming new substances called 
oxides. Water is hydrogen united with oxygen and its 
chemical name might therefore be oxide of hydrogen. 

When water is heated in an open vessel, evapora- 
tion from the surface of the liquid is more rapid as 
the temperature increases. Soon vapor is formed on 
the sides and bottom of the vessel and bubbles begin to 
rise which are at once condensed by the cooler parts 
of the liquid, thus making the familiar "singing" noise. 
Finally the liquid becomes so hot that the bubbles reach 
the surface without condensing, and then the water 
boils and goes off into the air as steam, an invisible 
gas. This occupies the small space between the spout 
of the tea-kettle and the cloud of vapor which is com- 
monly called steam, but is really finely divided drops 
of water. A cubic inch of water makes about a cubic 
foot of steam. 

The temperature at which pure water begins to boil 
at sea level is 212° Fahrenheit (or 100° Centigrade) 
and this temperature remains the same while the boil- 
ing continues. Increasing the heat simply increases 
the violence of the boiling. The steam given off is of 
the same temperature as the boiling liquid. Most pure 
liquids have a definite boiling point ; ether boils at 
100° F, alcohol at 173° F, turpentine at 315° F. 

When the pressure of the atmosphere on the surface 
of the liquid is less than at the sea level, as on a moun- 
tain, where there is not so much air above pressing 
down on the surface of the liquid, the temperature of 



Effect of 

Heating 

Water 



Boiling 
Point 



12 CHEMISTRY OF THE HOUSEHOLD. 

boiling is less. For example, the boiling point of water 
in Denver, Colorado, is about 202° F, and on the top 
of some of the mountains in the Himalayas, 180° F. 
People living in high mountain regions have difficulty 
in cooking with water or steam. 

Increasing the pressure on the surface of the liquid, 
on the other hand, raises the boiling point. This is 
seen when water boils in a confined space, as in a steam 
boiler. Under five pounds pressure of steam, water 
boils at about 22y° F and at 100 pounds pressure, at 
337° F. 

An increase in the boiling point of water is caused 
by dissolved substances. A very strong solution of 
common salt boils at about 226° F, and a solution of 
sugar — syrup or molasses — boils at an increasing tem- 
perature as the water is lost. 

The temperature at which a syrup boils, is a meas- 
ure of its thickness or density. In many modern cook- 
ery books temperature tests are given for boiling sugar 
in making confections, which vary from 215° for 
a thin syrup, up to 350'' for caramel. In making maple 
sugar a "sugar thermometer" is often placed in the 
boiling syrup. At a given temperature, which is high- 
er for sugar cakes than for soft sugar, the proper con- 
centration is reached. 
latent Considerable heat is absorbed by the process of boil- 
ing. It requires 966 times as much heat to change a 
pound of water at the boiling point into steam as it 
does to raise it one degree Fahrenheit. The heat 



Heat 



WATER. 



13 



which is used to change the state of the water without 
changing its temperature is called latent heat from the 
Latin word, meaning hidden. The "hidden heat" is 
given out again when the steam is condensed. This 
same quantity of heat is absorbed when the water 
evaporates slowly ; hence the great cooling effect of 
large bodies of water. 

When water is cooled it shrinks slightly until the 
temperature of 39° F is reached. On further cool- 
ing it to the freezing point, 32° F (or 0° Centigrade) 
it increases in volume, so that ice takes up more space 
than the same weight of water and consequently floats. 
If this were not so, lakes and streams would freeze 
solid in winter and it is doubtful if they would melt 
completely during the summer in the northern part 
of the United States. 

To melt ice, 144 times as much heat is required to 
change the ice at 32° F into water at 32° F, as to raise 
the temperature of the same quantity of water one 
degree Fahrenheit. This is the latent heat of melting 
and the same amount of heat is given out when water 
freezes. Water thus serves as the great temperature 
regulator for the earth, for by evaporating, much of 
the heat of summer is absorbed, and before freezing, 
a great deal of heat must be given out and absorbed. 

Water has a much greater capacity of absorbing heat 
than any other common substance. For example, one 
pound of water will absorb ten times as much heat in 
being raised one degree as a pound of iron. The great- 



Freezing 



Heat 
Absorption 



14 CHEMISTRY OF THE HOUSEHOLD. 

er absorbing capacity of water for heat explains why a 
kettle of fat heats up so much faster than the same 
weight of water under like conditions ; for the fat re- 
quires only one-third as much heat to raise it, say, to 
200° F, as does the water. 

THE ATMOSPHERE 

When we leave the sleeping room, we open the win- 
dows to admit air. We may with advantage treat 
our lungs to an air bath by standing at the open win- 
dow or by going out of doors for a few minutes to take 
in five or ten deep breaths. Next, perhaps, we shall 
use drafts of air to help us make a fire in the range 
or in a fire place. 
Air as a Air is a real substance. It can be weighed. The air 
in a room 15 feet by 20 feet by 10 feet high weighs 
210 pounds, and would fill ten ordinary water pails 
if liquified. Air will expand and may be compressed 
like other gases and it has been liquefied by intense cold 
and pressure. It requires considerable force to move 
it. When a bottle is full of air, no more can be poured 
in. Our houses are full of air all the time. It pervades 
all things — the cells and tissues of our bodies are full 
of air. 

Wood and some metals even contain a little. In 
breathing we take a little from the room, but it is im- 
mediately replaced by expired air, which is impure. 
Were there no exits for this air, no pure air could enter 
the house, and we should die of slow suffocation. The 



Substance 



THE ATMOSPHERE. 15 

better built the house the quicker the suffocation. Fortu- 
nately no house is air tight. Air does pass out through 
the walls and cracks, and comes in around doors and 
windows, but unless there is a great difference in the 
temperature indoors and out, this fresh air is neither 
sufficient to replace the bad air nor to dilute it beyond 
harm. Therefore in ordinary weather, the air of all 
rooms must be often and completely changed either by 
special systems of ventilation or by intelligent action 
in the opening of doors and windows. 

The atmosphere surrounds the earth to a depth of pressure 
fifty miles or more. The effect of gravity of the earth 
on this mass is to produce a pressure or weight of air 
on all things. This pressure is about fifteen pounds on 
each square inch, but we do not notice it, for the pres- 
sure is the same on all sides of us and the internal 
pressure in the cells of our bodies balances the external 
pressure of the atmosphere. 

If it were not for the pressure of the air, we could 
not drink lemonade through a straw or pump a pail of 
water. When we exhaust part of the air by suction, 
we remove part of the pressure over the liquid in the 
straw and the air pressure on the surface in the glass 
forces the liquid up the straw. The same principle 
applies in a pump — the air is partially taken off the top 
of the water in the pipe, and then the pressure outside 
forces the water up in the pipe and by a proper valve 
arrangement, it is made to run into the pail. See 
Fig. 9, 



i6 



CHEMISTRY OF THE HOUSEHOLD. 



Composition 
of Air 



Kitrogen 



The pressure of the atmosphere at the sea level is 
sufficient to force water up into a vacuum about 34 
feet vertically ; but owing to mechanical imperfections 
of pumps, the practical limit is 27 or 28 feet rise be- 
tween the surface of the water and the valve of the 
pump. It is customary to use a force pump if water 
is to be raised to a height above this. Fig. 10. 

Unlike water, air is not the result of a chemical union 
of two unlike simple gases. Nevertheless, air contains 
more than one substance. It is made up chiefly of two 
gases simply mixed together, and each exhibits its 
own characteristics to some extent. 

Pure air consists of oxygen, which we have found 
constitutes one-third of water, and of nitrogen (and 
argon). The oxygen forms about a fifth and the 
nitrogen four-fifths of the air. Besides these, several 
other gases are found in small but varying quantities. 

To the oxygen gas is due the power of air to support 
combustion (fire) and life. Oxygen unites chemically 
with most other substances, and were the air all oxy- 
gen, the combustible part of the earth would soon be 
consumed by its own fires. Fortunately four-fifths of 
the air is a gas that has little power of combination and 
this nitrogen serves to dilute the oxygen and to weaken 
its force, much as water would dilute and weaken a 
strong and powerful chemical. 

The most marked characteristic of nitrogen is its 
sluggishness or inertness. Nitrogen, like oxygen, is 
a tasteless, odorless, colorless gas. It is fourteen 



THE ATMOSPHERE. 



17 



times as heavy as hydrogen. Though nitrogen from 
the air unites with other elements with difficulty, it 
is found in all living tissues, both animal and vegetable, 
and when these decompose the familiar substance, am- 
monia, is formed. This is a compound of hydrogen 
and nitrogen. 





Fig. 9. Suction Pump. 



Fig. 10. Force Pump. 



Carbon dioxide is always present in the atmosphere. 
This is one of the countless combinations of carbon, 
the element present in all animal and vegetable mate- 
rials. Carbon is nearly pure in the form of charcoal. 
Soot, graphite or the black lead of lead pencils, and the 



Carbon 



l8 CHEMISTRY OF THE HOUSEHOLD. 

diamond are other forms. Carbon unites very readily 
with oxygen and the gas formed by their chemical 

Carbon u^ion is Called carbon dioxide because it contains two 
Dioxide parts of oxygcu to one of carbon. Wood, coal, gas — 
almost everything that will burn in the air — and even 
our own bodies contain carbon, though we would not 
suspect its presence because it is combined with other 
substances and has merged its own character in those 
of the substances of which it forms a part. All our 
food contains carbon in its combinations. 

When we breathe we take into our bodies the oxy- 
gen of the air. This oxygen is needed by the various 
organs and is carried in the blood from the lungs to all 
parts of the body. During the circulation the oxygen is 
taken up by the cells and replaced by carbon dioxide. 
This is brought back by the blood to the lungs and 
breathed out. If we remain long in a closed room, a 
portion of the oxygen of the air in the room and of the 
substance of our bodies is changed into carbon dioxide, 
which is unfit to breathe. This is the reason for the 
special need of ventilation in the sleeping room. 

Water Water in the form of vapor is constantly passing 

ofif into the air from the surface of bodies of water, 
from vegetation, and from animal organisms, as in- 
visible vapor. The amount of water vapor present 
in the air is very variable. Warm air will hold more 
vapor than cold air. Ordinarily on a pleasant day, the 
atmosphere holds between 60 per cent and 70 per cent 
of the possible amount of water vapor, 



The atmosphere. 



19 



When the air is saturated or at the dew point, a 
sHght lowering of the temperature causes the vapor to 
condense. That air will absorb only a certain amount 
of moisture explains why a draft of air is necessary 
when drying clothes within doors and why the wash- 
ing drys slowly on a damp day. 

The presence of vapor in the air is shown by bring- 
ing a pitcher of ice water into a warm room. The air 
against the cold surface of the pitcher is cooled until 
the dew point is reached, when it deposits part of its 
moisture. Any person who wears glasses knows the 
effect of such condensation in going into a warm room 
from out of doors on a cold day. That the air exhaled 
contains water may be shown by breathing upon any 
bright, cold surface. 

The discomfort we feel in a crowded room is largely 
due to the excess of moisture resulting from the 
breathing and perspiration of so many persons. The 
danger of going from a crowded reception or **tea" 
into the open air is also due to it. Crowded rooms 
become very warm, the air soon becomes saturated 
with vapor and cannot take away the perspiration from 
our bodies. Our clothes thus become moist and the 
skin tender. When we go into the colder, drier air, 
clothes and skin suddenly give up their load of mois- 
ture. Evaporation absorbs heat ; the heat is taken 
from our bodies and a chill results. There is much 
to learn concerning the ventilation of rooms for social 
purposes. 



Dew 
Point 



How a 
Chill is 
Produced 



20 CHEMISTRY OF THE HOUSEHOLD. 

^ ^jj The air also contains a very small amount of a gas 
called argon. This was discovered in 1894. It resem- 
bles nitrogen so closely that it long escaped detection. 
Several other gases are present in minute quantities. 

COMBUSTION . 

Very likely a fire must be built in the cook stove. 
In order that chemical combination may take place, 
the conditions must be right. The stove is so con- 
structed that a current of air can pass from under the 
grate through the fire box, and funnel, to the chimney, 
and we must arrange that this air current shall not be 
unduly obstructed, for fuel will not burn without 
oxygen. 
Kindling Substauccs differ greatly as to the ease or difficulty 

with which they may be made to burn, or in chemical 
terms, with which they may be made to unite with 
oxygen. The temperature to which a substance must 
be heated before it will take fire is called the kindling 
point. We therefore place light materials, like shav- 
ings, pitch-pine chips, or paper on the grate, twisting 
the paper and arranging all in such a way that oxygen 
has free access to a large surface ; upon this we place 
small sticks of wood, piling them across each oJ:her 
for the same reason, and on this, in turn, hard wood or 
coal. The large stick of wood or the coal cannot be 
kindled with a match, but the paper or shavings can, 
and these in burning will heat the wood until it takes 
fire which then will kindle the coal. 



Point 



COMBUSTION. 



21 



To kindle the fire, we unthinkingly light a match. 
The burning of the match repeats the same principle 
we have described. The match is made by dipping the 
ends of small sticks of wood into melted sulphur, a 
substance more easily kindled than wood. When the 
sulphur is dried, the match is tipped with a preparation 
of phosphorus. Phosphorus has such a low kindling 
temperature that friction of the match against any 
rough surface heats it sufficiently to set it on fire. In 
burning, this sets fire to the sulphur and this, in turn, 
kindles the wood. Paraffine now has replaced sulphur. 

The products (substances formed) of the burning 
match are oxide of phosphorus, oxide of sulphur, and 
carbon dioxide and water from the carbon and hydro- 
gen of the wood. As our coal fire burns, we have two 
different oxides of carbon formed — carbon monoxide 
composed ' of one part carbon and one part oxygen, 
and carbon dioxide having two parts oxygen to one of 
carbon. The carbon monoxide formed in the lower 
part of the fire rises through the burning coals, takes 
up more oxygen at the top of the fire and forms carbon 
dioxide. The blue flames seen over a hard coal fire 
are caused by carbon monoxide burning. Carbon 
dioxide does not burn, since in this form the carbon 
holds as much oxygen as possible. The drafts and 
dampers so regulate the supply of oxygen that the 
fire may burn rapidly or slowly and that the harmful 
products of combustion may be carried out of the 
house by way of the chnnney. 



Chemistry 
of a Match 



Products of 
Combustion 



Carbon 
Monoxide 



2.2 



CHEMISTRY OF THE HOUSEHOLD. 



Constant 
Composition 
of tiie Air 



Elements 



It might be thought that with the miUions of human 
beings and animals and countless fires constantly using 
oxygen and giving off carbon dioxide, that the atmos- 
phere would soon consist of a large proportion of car- 
bon dioxide. Nature has wonderfully provided for 
this. Carbon dioxide, which is the waste matter of 
animals, is one of the foods of plants. Thus the trees 
of the forest and the shrubs and plants of the garden 
are continually taking in the carbon dioxide and giv- 
ing out pure oxygen, so that the carbon dioxide is 
kept at about three or four parts in 10,000 of air. 

As has been said, wood consists mainly of the sub- 
stances, carbon, oxygen, hydrogen, and nitrogen, to- 
gether with other substances in small amounts. The 
growing tree has taken these simple substances from 
the air and earth and stored them up in a complex form 
as w®od. 

The chemist calls the simple substances out of which 
different things are made, elements. Carbon, oxygen, 
nitrogen, sulphur, phosphorus, silver, gold, copper, 
iron, lead, tin, mercury, zinc, aluminum are the chemi- 
cal elements familiar to most people. When the \Vood 
is burned, or oxidized, its elements are made into new 
combinations, but in the burning no substance is de- 
stroyed. Some of the new products are invisible, it 
is true, but that they exist may be proved in many 
ways. 

One of the fundamental laws of chemistry is the 
Law of Conservation of Matter (substance). This 
may be stated as follows : The weight of all the 



COMBUSTION. 



23 



products made in a chemical action is exactly equal to 
the weight of all the substances used. That is, the 
weight of the dry wood plus the weight of the oxygen 
required to burn it, equals the combined weight of car- 
bon dioxide, water, and ashes produced. Matter can 
neither be destroyed nor created — it can only be 
changed or transformed. Scientists have reason to be- 
lieve that there is just the same amount of oxygen, nit- 
rogen, sulphur, iron and of all the other elements in 
the universe at the present moment as there was at the 
beginning of things. 

A familiar form of nearly pure carbon is charcoal. 
It is made by heating wood for a time with a very 
small amount of air. The vola- 
tile parts of the wood are driven 
off, leaving the carbon. The old 
fashioned method of making 
charcoal is shown in Fig. 1 1, 
where the burning of part of the 
wood gave the heat necessary for 
the making of the charcoal. At ^^^- ^^• 
the present time, most charcoal is made by the de- 
structive distillation of hard wood in iron stills ; the 
products being charcoal, crude wood alcohol, crude 
acetic acid, together with gas and wood tar, which last 
are burned to give the heat for the process. 

Charcoal is a porous substance and has the power of 
absorbing into its pores gases and even particles of 



OoBServation 

of Matter. 




Charcoal Kiln. 



Charcoal 



24 CHEMISTRY OF THE HOUSEHOLD. 

coloring matter. A few pieces of charcoal added to 
the water in which flowers are standing, or plants 
growing, help to keep the water sweet by absorbing the 
impurities. Boneblack, a very finely powdered animal 
charcoal, is used to decolorize liquids. If it is mixed 
with a dark syrup, for instance, and the mixture vio- 
lently shaken, the color will be absorbed and filtration 
will give a nearly colorless syrup. 
Coal Coal is formed in almost every country on the 

earth, but the United States has the largest amount. 
It was originally wood and other carbonaceous mate- 
rial, once a part of living organism at a date of perhaps 
millions of years ago. During these years, the earth's 
crust has been subjected to slow upheavals and depres- 
sions, so that in some places, what was originally at 
the surface has been covered with thousands of feet of 
earthy matter, or possibly by the ocean. Under enor- 
mous pressure, the plants have been subjected to heat 
from the earth's interior. This is destructive distil- 
lation on the largest scale. 
Graphite In the making of coal if this distillation is com- 

plete, a substance called graphite is obtained. Graphite 
is the black lead used in lead pencils and in stove polish. 
It is a shiny, black mineral with a slippery feeling and 
is nearly lOO per cent carbon. If the distillation is 
less complete, hard coal, called anthracite containing 
about 90 per cent carbon, results. If still less per- 
fect, soft or bituminous coal, having varying per- 
centages of carbon, is formed. 



COMBUSTION. 25 

Where the process goes on under water, peat is p^^^ 
found. This is partially formed coal, but little dis- 
tilled and contains only about 40 per cent carbon. 

Besides carbon, these substances are made up of 
gases composed of carbon and hydrogen, called hydro- 
carbons. These gases give the yellowish and orange 
flames in a coal fire. Pure carbon does not burn with 
flame — it merely glows. Anthracite coal contains 
only from 3 to 4 per cent of volatile matter, but bi- 
tuminous coal may have 30 to 40 per cent of these 
hydro-carbon gases. 

Coke is made by the destructive distillation of soft coke 
coal. Like charcoal, it is chiefly carbon, but contains 
more mineral matter (ash). The coke obtained as a 
bi-product in the manufacture of coal gas is rather soft, 
but when coke is made as the principal product, it is 
hard and brittle. Coke makes a very hot lire without 
flame, but does not last as well as hard coal. The ash 
should be allowed to accumulate in the grate when 
burning it. Many consider it an improvement over 
soft coal for household use and it might be used to 
advantage more than it is. 

Graphite is so hard and compact that it cannot be 
burned. Anthracite ignites with some difficulty and 
then burns slowly with intense heat. 

Bituminous coal ignites readily and burns well when coking 
there is sufficient draft. The "coking" variety cakes 
over on top and the fire must be broken up to allow 
the air to penetrate the fire. Soft coal should be put 
on the fire in small amounts as otherwise the hydro- 



26 



CHEMISTRY OF THE HOUSEHOLD. 



carbon gases escape iinburned and thus much heat 
vakie is lost. Smoke is made up of finely divided 
particles of carbon and is always an indication of in- 
complete combustion and, therefore, loss. 



,>'^y\ 




r\i^ 



Fig. 12. Burner of a Blue Flame Oil Stove. 

Oil from tank (not shown) is forced np O, is vaporized in passing 
throvagh the straight tube, mixes with air at A, and burns with a blue 
flame at the top. 

Kerosene Kcroscnc and gasoline are also important fuels. Gas 
will be taken up under the subject of light. Petroleum 
is an oily liquid found in many places in large quanti- 
ties, particularly in Pennsylvania and Ohio. It is 
made up almost entirely of compounds of carbon and 
hydrogen ( hydro-carbons ) . 

When the crude petroleum from the Pennsylvania 
district is purified by distillation and other processes, 
the main product is kerosene. The lighter and more 
volatile products are gasoline, naphtha, and benzine 
— all three having much the same composition. Gaso- 
line is the most volatile. Among the heavier products 
are various lubricating oils, vaseline, and paraffin. 

In order to burn, kerosene must be vaporized. In 
the new blue flame oil stoves, various devices are em- 



COMBUSTION. 



27 



ployed to vaporize the oil. In F'ig. 12 the oil passes 
through a tube heated by the flame, where it is changed 
to vapor which is mixed automatically with air and is 
then burned. Sometimes an alcohol flame is used to 
start this process, but the flame of the burning oil 
itself continues it. A slight pressure of air is main- 
tained in the oil reservoir to give a constant small jet 
of oil to be vaporized. In other styles of stoves, the 
oil is fed automatically by gravity to a hollow ring, 
when it becomes heated to the point that it gives vapor. 
The vapor mixes with air and burns with a blue flame. 
Fig. 13. 




Blue Flame 
Oil Stoves 



Fig. 13. Blue Flame Oil Stove, Showing Oil Reservoir and Light- 
ing Ring. 



Gasoline is burned on much the same principle as GaioUne 
kerosene. It vaporizes much more easily and the pres- 
sure for the flow of the gasoline is furnished usually 
by having the tank a few feet above the burner. 



28 CHEMISTRY OF THE HOUSEHOLD. 

rj*»h '^^^ measure of safety of kerosene is the temperature 
^oi"t 2X which it will give off an inflammable gas. This 
is called the iia^h point and is determined by heating 
the oil slowly and observing the temperature at which 
a flash can be produced by applying a lighted taper 
to the surface of the oil. Below the flash point, there 
is no danger of explosion from oil. Most states in the 
United States have a legal flash point, or a fire test, 
below which standard kerosene cannot be sold. The 
flash point of good kerosene is 120'' F. The fire test 
is the temperature at which the oil will take fire and 
hum when a light is applied. This is about 30° F 
higher than the flash point. The ordinary tempera- 
ture of the room is above the flash point of gasoline, 
naphtha, benzine, etc. In other words, these sub- 
stances are constantly giving out an inflammable vapor. 
Fuel A comparison of the heating value of the various 

fuels will be of interest. Practical tests of the amount 
of steam produce.d in a steam boiler have shown that 
one cord of ordinary wood is approximately equal to 
one-half ton of coal ; a gallon of oil (or gasoline) is 
equal to about twelve pounds of coal; 1,000 cubic feet 
of coal gas is equal to 50 or 60 pounds of coal, or about 
four and one-half gallons of oil. Hard coal has a 
little higher fuel value than soft coal, because the com- 
bustion is commonly more perfect. Coke is nearly 
equal to hard coal by weight, but is much more bulky. 
It is usually sold by measure. A bushel of coke 
weighs 40 pounds, of anthracite 67 pounds, and of soft 



Value 



FOOD. 29 

coal y6 pounds. Damp wood is a much poorer fuel 
than dry wood, because so much heat is absorbed and 
wasted in changing the water into steam. 

The heat given oi¥ by a fuel is not the only point to 
be considered. In the cook stove, but a small portion 
of the heat given off by the solid fuel can be used for 
cooking, as most of it is radiated into the room or 
carried up the chimney. In the gas or oil stove, the 
flame may be applied exactly where it is wanted, so 
that the proportion of heat which can be used is much 
greater. Moreover, the flame can be shut off instantly 
when wanted no longer and all expense stopped. On 
the other hand, the range usually serves to heat the 
water of the hot water system, incinerate garbage, and 
in winter helps to heat the house. 

FOOD 

Having the fire well under way the housekeeper 
turns her attention to the breakfast. A great variety 
of chemical actions may here be considered. In the 
first place, why must we "eat to live ?" 

Wherever there is life, there is chemical change; 
and as a rule a certain degree of heat is necessary ^y ^» 
in order that chemical change may occur. Vegetation 
does not begin in the colder climates until the air be- 
comes warmed by the heat of the spring. When the 
cold of winter comes upon the land vegetation ceases. 

Since many animals live in temperatures in which 
plants would die, it is evident that they must have some 



30 



CHEMISTRY OF THE HOUSEHOLD. 



Com'buBtion 
in the Body 



Vital 
Temperature 



Air as 
Food 



source of heat in themselves. This is found in the 
union of the oxygen of the air breathed with car- 
bonaceous matter eaten as food and the formation of 
carbon dioxide and water, just as in the combustion of 
wood or coal. Only instead of this union taking place 
in one spot and so rapidly as to be accompanied by 
light, as in the case of fire, it takes place slowly and 
continuously in each living cell. Nevertheless, the 
chemical reaction seems to be identical. 

The heat of the human body must be maintained at 
98.5° F — the vital temperature — the temperature neces- 
sary for the best performance of the normal functions. 
Any continued variation from this degree of heat in- 
dicates disease. Especially important is it that there 
be no considerable lozvering of this temperature, for a 
fall of one degree is dangerous, since in that case the 
chemical changes necessary to the body cannot be car- 
ried out. 

The slow combustion or oxidation of the carbon 
and hydrogen of food cannot take place without an 
abundance of oxygen ; hence the diet of the animal must 
include fresh air — a point not always considered. 

The amount of oxygen taken in by the body daily is 
equal to the sum of all the other food elements. 

Except water, two-thirds of these foods consists of 
some form of starch or sugar — the socalled carbohy- 
drates, in which the hydrogen and oxygen are found in 
the same proportion as in water. 

The power to do mechanical work comes from the 



FOOD. 



31 



combustion of fuel. The body is a living machine 
capable of doing work, raising weights, pulling loads, 
and the like. The animal body also requires fuel in 
order to do such work as thinking, talking, even wor- 
rying. For the present, then, we will say that food is 
necessary, (i) to preserve the vital temperature and 
(2) to enable the body-machine to do its work. 

Suppose we begin our breakfast with fruit, say, an 
orange or a banana. Fruits are especially rich in 
sugars and these are composed of carbon, hydrogen, 
and oxygen. If sugar is placed upon a stove, it will 
melt and steam (water) will pass off into the air, 
leaving the black charcoal (carbon) on the stove. 
Moreover, sugars burn easily and fiercely. We shall 
get both heat and energy from our fruit. Within the 
body it will be changed into water and carbon dioxide- 
Fruits contain a large percentage of water; but the 
banana is capable of giving more energy and heat 'than 
the orange, because it has much less water and more 
sugar. Fruit loses in drying a large portion of its 
water, so that dried fruits contain a larger percentage 
of food materials than fresh fruits. For instance, 
raisins are 60 per cent grape sugar. 

Fruits consist of a loose net-work of a woody ma- 
terial holding the soft pulp and this woody fibre, called 
cellulose, is practically indigestible. Cooking softens 
this, making cooked fruits easier to digest. 



Fruit 



Cellulose 



32 CHEMISTRY OF THE HOUSEHOLD. 

SUGARS AND STARCHES. 

At breakfast some sugar from the sugar bowl may 
be added to the fruit. Many people add sugar tc the 
oatmeal or other cereal eaten, although it is often held 
by teachers of dietetics that this is not a good place to 
use it, for proper cooking and thorough mastication of 
the cereal will bring out a rich sweetness due to changes 
explained later. Country boys know how sweet a 
morsel is made by chewing raw grains, especially 
wheat. Possibly a glass of milk is taken at breakfast 
and this contains another kind of sugar — milk sugar — 
in about 5 per cent. Coffee and tea are usually sweet- 
ened, so that a considerable part of the breakfast may 
be of this class of foods — a quickly burning material 
giving heat and energy. 
Cane There are several different sugars recognized by 

chemists ; these are cane sugar or sucrose, grape sugar 
or glucose, milk sugar or lactose, and fruit sugar or 
levulose. Cane sugar is obtained from the juices of 
many plants, notably sugar beets, sugar cane, the 
palm, and as maple sugar from the rock-maple trees. 
Molasses and brown sugar are obtained during the 
manufacture of white sugar from sugar cane. Cane 
sugar is composed of carbon, hydrogen, and oxygen 
in the proportion of twelve parts of carbon to eleven 
parts of water. When sugar is heated it is chemically 
changed, more or less, according to the degree of heat 
and the rapidity with which it parts with its water. 



Sugar 



SUGARS AND STARCHES. 33 

Heating it gradually, we obtain first straw colored 
barley sugar, then brown caramel, and finally black 
carbon. 

Grape sugar is found in honey and in all ripe fruits. Grape 
It consists of carbon, hydrogen, and oxygen in some- "^" 
what different proportions from what they occur in 
cane sugar. It appears on the outside of dried fruits, 
such as raisins. It is only two-fifths as sweet as cane 
sugar. Large quantities are manufactured from corn 
starch. 

Milk sugar is similar to cane sugar in composition. jjiu^ 
It is obtained from the whey of milk. It is hard ^"^" 
and gritty and not very sweet to taste. When milk 
sours, it is because this sugar is fermented and changed 
into lactic acid. The acid causes the milk to curdle. 

Fruit sugar or levulose occurs with glucose (grape j-j.^-^. 
sugar) in fruits. It is about as sweet as cane sugar ^"^" 
but it does not crystallize. 

A marked characteristic of all sugars is their solu- 
bility and all but the last are crystalline substances, 
that is, will form crystals. 

At breakfast bread, toast, or some cereal like oat- 
meal or wheat, usually follows the fruit course. 
These foods are prepared from grains (seeds) and 
contain much nutriment in a condensed form. They 
supply the body with starch and some nitrogenous 
food. But the body cannot use starch as such. It 
must be changed into a form of sugar called starch 
sugar, or maltose. While we are following Mr. Glad- 



starch 



34 



CHEMISTRY OF THE HOUSEHOLD. 



Source 
of Starch 



stone's rule and chewing each mouthful of our toast 
twenty-five times, we will consider what starch is like 
and how it is made available for use. 

Starch is found in greater or less abundance in all 
plants and is laid up in large quantities in the seeds of 
many species. See Fig. 14. Rice is nearly pure 
starch ; wheat and the other cereals contain sixty to 
seventy per cent of it. Some tubers, such as potatoes, 
contain it although in less quantity — ten to twenty per 
cent. 

It is formed by means 
of the living plant-cell 
and the sun's rays, from 
the carbon dioxide and 
water contained in the 
air and it is the end of 
the plant - life — the 
stored energy of the 
summer. It is prepared 
and stored by the parent 

for the food for the young plant until the latter can 

start its own starch factories. 

Starch in its common forms is insoluble in water. It 
dissolves partially in boiling water, forming a trans- 
parent jelly when cooled, as every housekeeper knows. 
The cellulose which occurs in various forms in the 
shells and skins of fruits, in their membraneous parti- 
tions, and in cell walls, is an allied substance. 




Fig. 14. Starch Much Magnified 
a, Potato Starch; b, Corn Starch. 



SUGARS AND STARCHES. 



35 



DIGESTION 

Digestion is primarily synonymous with solution. 
All solid food materials must become practically solu- 
ble before they can pass through the walls of the di- 
gestive system. Starch and like materials must be 
transformed into soluble substances before absorption 
can take place. Cane-sugar, though soluble, has to 
undergo chemical change before it can be absorbed. 
By these changes it is converted into grape and fruit 
sugars. These and milk sugar are taken directly or 
with little change into the circulation. To this fact is 
due a large part of the great nutritive value of the 
dried fruits, as raisins, dates, and figs, and the advan- 
tage of milk-sugar over cane-sugar for children or in- 
valids. 

Under certain conditions — weakened digestive power 
or excess of sugar — cane-sugar may remain so long 
in the stomach before the change takes place that fer- 
mentation sets in and a ''sour stomach" results. This 
is one of the dangers of too much candy. 

The chemical transformations of starch and sugar 
have been very carefully and scientifically studied with 
reference to brewing and wine-making. Several of 
the operations concerned necessitate great precision in 
respect to temperature and length of time, and these 
operations bear a close resemblance to the process 
of bread-making by means of yeast. 

There are two distinct means known to the chemist 
by which starch is changed to sugar. One is by the 



Digestion 
of Starch 



Starch 
Conversion 



Ferments 



Conversion 
in the Body 



36 CHEMISTRY OF THE HOUSEHOLD 

use of acid and heat, which changes the starch into 
sugar, but can go no farther. The other is by the use 
of a class of substances called ferments, some of which 
have the power of changing starch into sugar, and 
others of changing the sugar into alcohol and carbon 
dioxide. These ferments are very important in all 
vegetable and animal life. Some are formed by small 
plants like yeast, which is often present in the air. 

Fig. 15. 

Among the well known ferments is one formed in 
sprouting grain, which is called diastase or starch con- 
verter, and under the influence of warmth, changes the 
starch into a sugar. The starch first 
takes up water ; then under the in- 
fluence of the ferment, is changed 
into maltose, a form of sugar 
which is easily soluble in water. A 
similar process is carried on in the 
preparation of the malted foods on 
the market. 

The sanie cycle of chemical changes goes on in the 
human body when starchy substances are taken as 
food. Such food is moistened with saliva and warmed 
in the mouth, becoming well mixed through mastica- 
tion. It thereby becomes impregnated with ptyalin, 
a ferment in the saliva, which can change starch into 
sugar, as can the diastase of the malt. The mass then 
passes into the stomach and the change, once begun, 
goes on. In the intestines the sugar formed is absorbed 
into the circulatory system and by the life proc- 




Fig. 15. 

Yeast Highly 

Magnified. 



COOKING. 



37 



esses, is oxidized, that is, united with more oxygen 
and changed finally into carbon dioxide and water, 
from which it was made by the help of plant life and 
sun light. 

No starch is utilized in the human system as starch. 
It must undergo transformation before it can be ab- 
sorbed. Therefore, starchy foods must not be given to 
children before the secretion of the starch converting 
ferments has begun, nor to any one in any disease 
where the normal action of the glands secreting these 
ferments is interrupted. Whatever starch passes out 
of the stomach unchanged, meets with a very active 
converter in the intestinal juice. If grains of starch 
escape these two agents, they leave the system in the 
same form as that in which they entered it. 



Digestion 
of Starch 



Early man, probablv, lived much like the beasts, 
taking his food in a raw state. Civilized man requires 
much of the raw material to be changed by the action 
of heat into substances more palatable and already 
partly digested. 

The chemistry of cooking the raw materials is very 
simple. It is in the mixing of incongruous materials 
in one dish or one meal that complications arise. 

The cooking of starch, as rice, farina, etc., requires 
little explanation. The starch grains are prepared by 
the plant to keep during a season of cold or drought 
and are very close and compact ; they need to be 



Cooking 
of Starch 



38 CHEMISTRY OF THE HOUSEHOLD. 

swollen and distended by moisture in order that the 
chemical change may take place readily. Starch grains 
may increase to twenty-five times their bulk by absorb- 
ing water. 

The cooking of the potato and other starch-contain- 
ing vegetables, although largely a physical or mechani- 
cal process is very necessary as a preparation for the 
chemical actions of digestion ; for raw starch has been 
shown to require a far longer time and more digestive 
power than cooked starch. Change takes place slowly, 
even with thorough mastication, unless the starch is 
swollen and heated, and, in case the intestinal secre- 
tion is disturbed, the starch may not become converted 
at all. 

Bread Oi^^i* brcakfast will undoubtedly contain bread. 

Bread of some kind has been used by mankind from 
the first dawn of civilization. During the earlier 
stages it consisted chiefly of powdered meal and water 
baked in the sun or on hot stones. This kind of bread 
had the same characteristics as the modern sea-biscuit, 
crackers, and hoe cakes, as far as digestibility was 
concerned. It had great density ; it was difficult to 
masticate ; and the starch in it presented but little 
more surface to the digestive fluids than that in the 
hard compact grain, the seed of the plant. 

Experience must have taught the semi-civilized man 
that a light porous loaf was more digestible than a 
dense one. Probably some dough was accidentally left 
exposed ; yeast plants settled upon it from the air ; 



Bread 



or Yeast 



COOKING. 39 

fermentation set in, and the possibility of porous bread 
was thus suggested. 

A light, spongy, crisp bread with a sweet, pleasant weai 
taste, is not only aesthetically but chemically con- 
sidered the best form in which starch can be presented 
to the digestive organs. The porous condition is de- 
sired in order that as large a surface as possible may 
be presented to the action of the chemical converter, 
the ptyalin of the saliva, and later to other digestive 
ferments. There is also better aeration during the 
process of mastication. 

Very early in the history of the human race, leavened Leaven 
bread seems to have been used. This was made by 
allowing flour and water to stand in a warm place until 
fermentation had well set in. A portion of this dough 
was used to start the process anew in fresh portions of 
flour and water. This kind of bread had to be made 
with great care, for germs different from yeast might 
get in, forming lactic acid — the acid of sour milk — 
and other substances unpleasant to the taste and harm- 
ful to the digestion. 

A sponge made from perfectly pure yeast and kept 
pure may stand for a long time after it is ready for 
the oven and still show no signs of sourness. 

On account of the disagreeable taste of leaven and 
because of the possibility that the dough might reach 
the stage of putrid fermentation, chemists and physi- 
cians sought for some other means of rendering the 
bread light and porous. The search began almost as 



40 CHEMISTRY OF THE HOUSEHOLD. 

soon as chemistry was worthy the name of a science, 
and one of the early patents bears the date 1873. Much 
time and thought have been devoted to the perfecting 
of unfermented bread; but since the process of beer- 
making has been universally introduced, yeast has 
been readily obtained, and is an effectual means of giv- 
ing to the bread a porous character and a pleasant 
taste. Since the chemistry of the yeast fermentation 
has been better understood, a change of opinions has 
come about, and nearly all scientific and medical men 
now recommend fermented bread, if well baked. 

Chemistry of ^^^^ chcmical rcactious concerned in bread-making 

Bread-Making ^j.^ similar to thosc iu beer-making. To the flour and 
warmed water is added yeast, a microscopic plant, 
capable of causing the alcoholic fermentation. The 
yeast begins to act at once, but slowly; more rapidly 
if sugar has been added and the dough is a semi-fluid. 
\^'ithout the addition of sugar no change is evident to 
the eye for some hours, as the fermentation of starch 
to sugar by the diastase present gives no gaseous 
products. The sugar is decomposed by the yeast plant 
into alcohol and the gas, carbon dioxide ; the latter 
product makes itself known by the swelling of the 
whole mass and the bubbles which appear on the sur- 
face. 

It is the carbon dioxide, which causes the sponge- 
like condition of the loaf by reason of the peculiar 
tenacity of the gluten, one of the constituents of wheat. 
It is a well-known fact that no other kind of grain will 



COOKING. 



41 



make so light a bread as wheat. It is the right pro- 
portion of gluten (a nitrogenous substance to be con- 
sidered later) which enables the light loaf to be made 
of wheat flour. 

The production of carbon dioxide is the end of the 
chemical process. The rest is purely mechanical. 

The baking of the loaf has for its object to kill the 
ferment, to heat the starch sufficiently to render it 
easily soluble, to expand the carbon dioxide and drive 
off the alcohol, to stiffen the gluten, and to make chem- 
ical changes which shall give a pleasant flavor to the 
crust. The oven must be hot enough to raise the tem- 
perature of the inside of the loaf to 212° F, or the 
bacteria will not all be killed. A pound loaf, four 
inches by four inches by nine inches long, may be 
baked three-quarters of an hour in an oven where the 
temperature is 400" F, or for an hour and a half, when 
the temperature during the time does not rise above 
350° F. Quick baking gives a white loaf, because the 
starch has undergone but little change. The long, 
slow baking gives a yellow tint, with the desirable 
nutty flavor, and crisp crust. Different flavors in 
bread are supposed to be caused by the different 
varieties of yeast used or by bacteria, which are pres- 
ent in all doughs, as ordinarily prepared. 

The brown coloration of the crust, which gives a 
peculiar flavor to the loaf, is caused by the formation 
of substances analogous to dextrine and caramel, due 
to the high heat to which the starch is subjected. 



Object of 
Saking 



The Crust 



42 CHEMISTRY OF THE HOUSEHOLD. 

One hundred pounds of flour are said to make from 
126 to 150 pounds of bread. This increase of weight 
is due to the incorporation of water, possibly by a 
chemical union, as the water does not dry out of a loaf, 
as it does out of a sponge. The bread seems moist when 
first taken from the oven, and dry after standing some 
hours, but the weight will be found to be nearly the 
same. It is this probable chemical change which makes 
the difference, to delicate stomachs, between fresh 
bread and stale. A thick loaf is best when eaten after 
it is twenty-four hours old, although it is said to be 
''done" when ten hours have passed. Thin biscuit do 
not show the same ill effects when eaten hot. 

The bread must be well baked in any case, in order 
that the process of fermentation may be stopped. If 
this be stopped and the mastication be thorough, so 
that the bread when swallowed is in finely divided por- 
tions instead of in a mass or ball, the digestibility of 
fresh and stale bread is about the same. 

Water The cxpausiou of water or ice into more than seven- 
teen hundred times its volume of steam is sometimes 
taken advantage of in making snow-bread, water-gems, 
etc. It plays a part in the lightening of pastry and 
crackers. 

Air, at 70 degrees, doubles its volume at a tempera- 
ture of 560 degrees F, so that if air is entangled in a 
mass of dough, it gives a certain lightness when the 
whole is baked. This is the cause of the sponginess 
of cakes made with eggs. The viscous albumen or 



COOKING. 



43 



''white of egg'' catches the air and holds it, even when 
it is expanded, unless the oven is too hot, when the 
sudden expansion is liable to burst the bubbles and the 
cake falls. 

FATS 

If cream instead of milk is used on the cereal or in 
the coffee, this with the butter on the bread, will add 
a considerable amount of another important food, 
fat. Fats form a large class of food stuffs which in- 
clude the animal fats like cream, butter, suet, lard, 
cod liver oil and tallow, and vegetable fats like olive 
and cotton-seed oils, etc. Within the animal body all 
fats are liquids, being held in little cells which make 
up the fatty tissue. 

The digestion of fats is probably something like a 
process of soap making. With the intestinal fluids, 
the bile especially, the fats form an emulsion in which 
the globules are finely divided, and in some way are 
rendered capable of passing through the membranes 
into the circulatory system. The change, if any, does 
not destroy the properties of the fatty matters. 

If we define cooking as the application of heat, then 
whatever we do to fats in the line of cooking is liable 
to hinder rather than help digestibility. 

Fats may be heated to a temperature far above that 
of boiling water without showing any change ; but 
there comes a point, different for each fat, where re- 
actions take place, the products of which irritate the 
mucous membranes and therefore interfere with diges- 



Digestion 
of Fats 



Cooking' 
of Fats 



44 CHEMISTRY OF THE HOUSEHOLD. 

tion. It is the volatile products of such decomposition 
which cause the familiar action upon the eyes and 
throat during the process of frying, and also, the tell- 
tale odors throughout the house. The indigestibility of 
fatty foods, or foods cooked in fat, is due to these 
harmful substances produced by too high temperature. 

Composition Many fats are solid at ordinary temperatures, while 

others are always liquids, but all fatty materials have 
a similar composition. When pure they contain only 
carbon, hydrogen, and oxygen. They differ from 
starch and sugar in the proportion of oxygen to the 
carbon and hydrogen, there being very little oxygen 
relatively in fats, hence more must be taken from the 
air for their combustion. If persons eat much fat they 
must have more fresh air to burn it. A person confined 
to the house needs to be careful what fats, and how 
much, are taken. 

Heat from ^^c pouud of starch rcquircs one and two-tenths 

^**^ pounds of oxygen, while one pound of suet requires 
about three pounds of oxygen for perfect combustion. 
This combustion of oxygen with the large amoimt of 
hydrogen, as well as with the carbon, results in a 
greater quantity of heat from fat, pound for pound, 
than can be obtained from starch or sugar. Experi- 
ments indicate that the fats yield more than twice as 
much heat as the carbohydrates ; hence people in 
Arctic regions use large amounts of fat and every- 
where the diet of winter may safely contain more fat 
than that of summer. 



NITROGENOUS FOODS. 



45 



Both fats and carbohydrates are the sources of the 
energy or work done by the body as well as the heat 
to keep up the vital temperature and they must be 
increased in proportion as the mechanical work of the 
body increases. A man breaking stone needs more fat 
or starch than the student. If a quantity is taken at 
any one time greater than the body needs for im- 
mediate work, the surplus will be deposited as fat, and 
this will be drawn in case of a lack in the future sup- 
ply of either ; it is like a bank account. 



Food 

a Source 

of Energy 



NITROGENOUS FOODS 

The animal body is more than a machine. It re- 
quires fuel to enable it not only to work but also to 
live, even without working. A part of the food eaten 
must go to maintain the body, for while the inani- 
mate machine is sent periodically to the repair-shop, the 
living machine must do its own repairing, day by day 
and minute by minute. 

The adult animal lives, repairs waste, and does 
work ; while the young animal does all these and more 
— it grows. For growth and repairs something else 
is needed beside starch and fat. 

The muscles are the instruments of motion, and 
they must be nourished in order that they may have 
power. The nourishment is carried to them by the 
blood in which, as well as in muscular tissue, there 
is found a food element which we have not heretofore 
considered, namely, nitrogen. It has been proved that 
the use of the muscles and the brain sets free certain 



Nitrogen 
Necessary 



46 



CHEMISTRY OF THE HOUSEHOLD. 



Proteids 



Gelatinoids 



nitrogenous compounds which pass out of the system 
as such, and this loss must be suppHed by the use of 
some kind of food which contains nitrogen. Starch 
and fat do not contain this element ; therefore thev 
cannot furnish it to the blood. 

The American breakfast will probably include meat, 
fish, or eggs. These are examples of the nitrogenous 
food-stuffs. Nitrogenous food compounds are some- 
times classed together under the name of proteins. 
These may be divided into proteids, gelatinoids, and 
extractives. 

The proteids all resemble albumin, which is found 
nearly pure in the white of an tgg. These in some 
form are never absent from animal and vegetable or- 
ganisms. They are most abundant in animal flesh and 
in the blood. Other common articles of diet belong- 
ing to this group in addition to albumin, are the curd 
of milk (casein), the lean of animal flesh and fish 
and gluten of wheat, and the legumin of peas and 
beans. The proteids are the most important nitro- 
genous food materials. They build up and repair the 
muscles, tendons, cartilage, bones, and skin and supply 
the albumin of the blood and other fluids of the body. 

The animal skeleton — horns, bones, cartilage, con- 
nective tissues, etc. — contains nitrogenous com- 
pounds which are converted by boiling into substances 
that form with water a jelly-like mass. These are 
known as the gelatinoids and are so named because of 
their resemblance to gelatin. Although somewhat 



NITROGENOUS FOODS. 



47 



similar to the proteids in composition they are not 
thought to be true flesh formers. However, they do 
help out the proteids in some unknown way. 

The chief constituent of the connective tissues of 
meats is collagen. This is insoluble in cold water, but 
in hot water becomes soluble and yields gelatin. Col- 
lagen swells when heated and when treated with 
dilute acids. Steak increases in bulk when placed 
over the coals, and tough meat is rendered tender by 
soaking in vinegar. Meat a few days old is tough, 
for the collagen is dry and hard. In time it becomes 
softened by acids which are secreted by bacteria either 
in or on the meat ; the meat thus becomes tender and 
easily masticated. Tannic acid has the opposite effect 
upon collagen, hardening and shrinking it. This ef- 
fect is taken advantage of in tanning, and is the dis- 
advantage of boiled tea as a beverage, since tea always 
contains a little of this tannic acid when freshly made 
and much more if the tea is boiled. 

The last class of nitrogenous compounds are the 
extractives, so called because they are readily extracted 
by water from meat where they principally occur. The 
proteins of this class are thought to have little value 
as food, but they give the flavor to meats, etc., and are 
therefore of great importance. They are stimulants, 
somewhat of the nature of caftein of coffee and the 
thein of teat 



Collagen 



Extractives 



48 CHEMISTRY OF THE HOUSEHOLD. 

COOKING OF NITROGENOUS FOOD-STUFFS. 

Cooking should render nitrogenous food more solu- 
ble because here, as in every case, digestibility means 
solubility. Egg albumin is soluble in cold water, buv 
coagulates at about i6o° F. At this point it is ten- 
der, jelly-like, and easily digested, while at a higher 
temperature it becomes tough, hard and dissolves with 
difficulty. Therefore, when the white of ^gg (al- 
bumin), the curd of milk (casein), or the gluten of 
wheat are hardened by heat, a much longer time is 
required to effect solution. 

Albumin As prcviously stated, Qgg albumin is tender and 

jelly-like when heated from i6o° F to i8o° F. This 
fact should never be forgotten in the cooking of eggs. 
Raw eggs are easily digested and are rich in nutri- 
ment ; when heated just enough to coagulate the al- 
bumin or *'the white," their digestibility is not ma- 
terially lessened ; but when boiled, the albumin is 
rendered much less soluble. 

In frying eggs, the fat often reaches a temperature 
of 300° or over — far above that at which the albumin 
becomes tough, hard, and well-nigh insoluble. 

There is much albumin in the blood, therefore the 
juices of meat extracted in cold water form a weak 
albuminous solution. If this be heated to the right 
temperature the albumin is coagulated and forms the 
"scum" which many a cook skims oft* and throws away. 
In doing- this she wastes a portion of the nutriment. 



NITROGENOUS FOODS. 49 

Experiments on the digestibility of gluten have Gluten 
proved that a high temperature largely decreases its 
solubility. Subjected to artificial digestion for the 
same length of time, nearly two and one-half times 
as much nitrogen was dissolved from the raw gluten 
as from that which had been baked. 

When gluten is combined with starch, as in the 
cereals, the difficulties of correct cooking are many, 
for the heat which increases the digestibility of the 
starch decreases that of the gluten. 

Experiment.- The gluten in wheat flour may be ob- 
tained as follows: Place half a cupful of flour in a 
muslin bag and knead under water. The starch will 
work out through the bag. After a time all the starch 
may be so separated. A brown, elastic, stringy mass 
remains in the muslin. This is gluten, the nitrogenous 
part of the flour. 

The same principle of cooking applies to casein of casein 
milk, although to a less extent. There seems to be no 
doubt that boiling decreases its solubility, and con- 
sequently, its digestibility for persons of delicate di- 
gestive power. 

The nitrogenous substances of meat consist of solu- Meat 
ble albumin, chiefly in the blood and juices, the al- 
buminoids of the fibres, the gelatinoids of the connect- 
ing tissues, and the extractives. The cooking should 
soften and loosen the connective tissue, so that the lit- 
tle bundle of fibre which contains the nutriment may 
fall apart easily when brought in contact with the 



so 



CHEMISTRY OF THE HOUSEHOLD. 



Broth 

and 

Soup 



Effect of 

Temperature 

on Meat 



teeth. Any process which toughens and hardens the 
meat should be avoided. 

When it is desired to retain the juices within the 
meat or fish, it should be placed in boiling water so 
that the albumin of the surface may be hardened and 
prevent the escape of the albumin of the interior. The 
temperature should then be lowered and kept between 
i6o and i8o degrees during the time needed for the 
complete breaking down of the connective tissues. 

When the nutriment is to be used in broths, stews, 
or soups, the meat should be placed in cold water, heat- 
ing very slowly and the temperature not allowed to 
rise above i8o° F until the extraction is complete. The 
extracted meat still retains the greater part of its 
original proteid substances. It is tasteless and un- 
inviting, but when combined with vegetables and 
flavoring materials may be made into a palatable and 
nutritious food. 

Experiment. To show the effect of water at dif- 
ferent temperatures upon raw meat, place a bit of lean 
meat about as large as the finger in a glass of cold 
water and let it stand an hour. The water becomes 
red, and the meat grows white. Pour off this water 
and boil it. A scum rises to the surface. The albu- 
min dissolved has been rendered insoluble by heat. 

Put a bit of raw meat into boiling water, and boil it 
hard several minutes. The meat is toughened by the 
process. The outside of the meat is hardened first, 
and very little of the nutriment dissolves in the water. 



of Froteids 



FOOD. SI 

Put the meat into cold water and bring the tem- 
perature slowly to the boiling point; then allow it to 
simmer gently for some time. The meat is tender, and 
some of the nutriment is in the water. This is the 
method employed in making a stew. A little fat which 
is always present even between the fibre of the lean 
meat will be melted out and rise to the top of the 
water. 

We have seen that the ferment in the saliva changed Digestion 
the starch into a sugar. The ferment in the gastric 
juice, pepsin, with the help of an acid (principally 
hydrochloric acid) changes the albuminoids into pep- 
tones in the stomach. This change is completed in the 
intestines. The peptones are soluble in water and are 
absorbed into the blood. 

SUMMARY OF THE EFFECTS OF COOKING 

The object of all cooking is to make the food-stui¥s 
more palatable or more digestible, or both combined. 
In general, the starchy foods are rendered more di- 
gestible by cooking; the albuminous and fatty foods 
less digestible. The appetite of civilized man craves 
and custom encourages the putting together of raw 
materials of such diverse chemical composition that 
the processes of cooking are also made complex. 

Bread — the staff of life — requires a high degree of 
heat to kill the plant-life, and long baking to prepare 
the starch for solution ; while, by the same process, 
the gluten is made less soluble. Fats, alone, are easily 
digested, but in the ordinary method of frying, they 



52 CHEMISTRY OF THE HOUSEHOLD. 

not only may become decomposed themselves, and 
therefore injurious ; but they also prevent the necessary 
action of heat, or of the digestive ferments up^n the 
starchy materials with which the fats are mixed. 

The effects of cooking upon the solubility of the 
three important food-principles may be broadly stated 
thus : 
Effeci on Stavcky foods are made more soluble by long cook- 

soiubihty -j^g ^^ moderate temperatures or by heat high enough 
to change a portion of the starch to dextrine, as in 
the brown crust of bread. 

Nitrogenous foods. The animal and vegetable al- 
bumins are made less soluble by heat ; the gelatinoids 
more soluble. 

Fats are readily absorbed in their natural condition, 
but are decomposed at very high temperatures and 
their products become irritants. 

MINERAL MATTER 

The remaining ingredient of the food of our break- 
fast to be considered is the mineral matter which con- 
stitutes the ash when food-products are burned. There 
is only 5 or 6 per cent of mineral elements in our bod- 
ies, but these materials are necessary to life and health. 
They are found chiefly in the bones and teeth, but are 
present also in the flesh, blood, and other fluids. Phos- 
phate of calcium forms the principal mineral part of 
the bones. 

Common ^^^^ ^^^^^ ^^'^ ^'^^ coutains a small amount of mineral 

^*^* matter which forms the ashes when food is burnecl, 



MINERAL MATTER. 53 

This mineral matter gives the body the mineral salts 
which it needs ; but in addition to this, most people de- 
sire and eat a considerable quantity of common salt 
every day. The amount eaten is far in excess of the 
sodium and chlorine the body requires, though sodium 
is an important constituent of many of the fluids of the 
body, and chlorine is found in hydrochloric acid of the 
gastric juice, the digestive fluid of the stomach. A 
great diversity of opinion exists as to the desirability 
of much salt in the diet, but the balance of evidence in- 
dicates that a liberal amount of salt is not harmful, but 
rather beneficial. 

Experiment. To show the mmeral part of bones, 
place a moderate sized bone on a hot coal fire for half 
an hour or longer. 

To show the gelatinoids of bones, place a small bone 
in a shallow dish and cover with strong vinegar or 
weak hydrochloric acid (muriatic acid) and let stand 
over night or longer. The acid \\\\\ dissolve out the 
phosphate of calcium leaving the animal matter. 

Coffee, an important part of the breakfast to most Flavor 
people, introduces an important feature of the chem- 
istry of cooking — the production of the proper flavor. 
The chemical changes involved are too subtile for ex- 
planation here — indeed many are not understood. The 
change in the coffee berry by roasting is a familiar il- 
lustration. The heat of the fire causes the breaking 
up of a substance existing in the berry, and the forma- 
tion of several new ones. If the heat is not sufficient, 



Production 



54 CHEMISTRY OF THE HOUSEHOLD, 

the right odor will not be given ; if it is too great, the 
aroma will be dissipated into the air, or the compound 
will be destroyed. 

Broiling steak is another illustration — a few seconds 
too long, a few degrees too hot, and the delicate morsel 
becomes an irritating mass. The chemistry of flavor- 
producing is the application of heat to the food material 
in such a way as to bring about the right changes and 
only these. Flavors in addition to the pleasure they 
give to eating have the advantage of stimulating the 
flow of digestive fluids and making digestion more 
easy. 

DECAY 

The clearing away of the breakfast introduces to the 
housekeeper two important problems: — (i) the pres- 
ervation of the remaining food from decay; (2) the 
proper cleaning of the articles used during the meal 
and its preparation. 

Decay is caused by minute vegetable organisms 
known as moulds and bacteria. Both are present in 
the air either as the plants themselves or as their 
spores, the reproductive cells, ready to grow whenever 
they fall upon suitable soil. When these grow upon 
animal or vegetable substances, a variety of new com- 
pounds are formed, many of them taking oxygen from 
the air, so that finally the carbon becomes carbon diox- 
ide, the hydrogen is oxydized to form water, and the 
other elements in their turn also become oxides, so 
that the decaying substance is utterly destroyed and 



Decay Not 



DECAY, 55 

new substances made in its place. When organic sub- 
stances are protected from the action of these living 
plants, decay will not ensue. 

The old idea was that oxygen caused decay, but 
many experiments disprove this. Oxveen alone does caused by 

. ' , Oxygen Alone 

not produce this result, but oxygen with ''germs" will 
do so. These "germs" develop much more slowly in 
the cold, so that food is placed in the refrigerator or 
in a cool place and away from the dust. 

The problems introduced by these living plants, their 
life history and their work, as well as the methods of 
prevention and care against their ravages, belong 
rather to household bacteriology than to chemistry. 
We are ready therefore to pass on to our next prob- 
lem, that of cleaning. 



TEST QUESTIONS 

The following questions constitute the ''written reci- 
tation" which the regular members of the A. S. H. E. 
answer in writing and send in for the correction and 
comment of the instructor. They are intended to 
emphasize and fix in the memory the most important 



points in the lesson. 



CHEMISTRY OF THE HOUSEHOLD. 

PART I, 



Read Carefully. Place your name and address on the first 
sheet of the test. Use a light grade of paper and write on one 
side of the sheet only. Do not copy answers from the lesson 
paper. Use your own words, so that your instructor may know 
that you understand the subject. Read the lesson paper a num- 
ber of times before attempting to answer the questions. 



1. What do you understand a "chemical element" to 

be? Name all that you have ever seen. 

2. What is a "saturated solution?" 

Name the substances usually found in the 
house which are soluble in water. 

3. What causes atmospheric pressure? Explain 

some effects of it. 

4. Why must the diet of animals include fresh air ? 

5. Explain the efifect of cooking on starch, (b) On 

fats, (c) On proteids. 

6. What are the products of combustion in burning 

coal or wood ? 

7. What is meant by "conservation of matter?" 

8. How can the boiling point of water be raised? 

How may it be lowered? 



CHEMISTRY OF THE HOUSEHOLD. 

9. V/hat is meant when It is said that a chemical 
substance always has the same composition ? 

10. What is "latent heat?" 

11. What can you say of the composition of meat? 

12. Explain the physical and chemical changes which 

starch must undergo before it is absorbed into 
the circulation. 

13. What can you say of the chemistry of bread- 

making ? 

14. Why is distilled water pure? 

15. Explain the composition of water. 

16. Describe the chemistry of a sulphur match. 

17. How is charcoal prepared ? How is coke made ? 

18. Why does the proportion of carbon dioxide in the 

atmosphere not increase? 

19. In what different ways is food used In the body? 

20. Do you understand all parts of this lesson paper? 

If not, what part is not clear? 

Note. — After completing the test sign your full name. 



CHEMISTRY OF THE HOUSEHOLD 

A Day's Chemistry 
PART II. 



CLEANING 

The cleaning of the dishes, silver, cutlery, and linen 
introduces a great variety of chemical problems. The 
subject of the chemistry of cleaning may well include 
with the daily task of dishwashing, the equally im- 
portant ones of house cleaning and laundry work. 

The various processes of housework give rise to 
many volatile substances, such as the vapor of water 
or fat. If not carried out of the house in their vapor- 
ous state these cool and settle upon all exposed sur- 
faces, whether walls, furniture, or fabrics. This thin 
film entangles and holds the dust, clouding and soil- 
ing with a layer more or less visible everything within 
the house. The fires and lights give out smoky de- 
posits of incomplete coijibustion. The dishes are soiled 
with waste from all kinds of foods — starch, grease, al- 
bumin, milk, gums, or gelatines and the juices of 
fruits. 

Dust alone might be removed from most surfaces 
with a damp or even with a dry cloth, or from fabrics 
by vigorous shaking or brushing; but usually the 
greasy or sugary deposits must first be broken up and 
the dust thus set free. This must be accomplished 
without harm to the material which is dirty. 



56 CHEMISTRY Of THE HOUSEHOLD. 

Cleaning, then, involves two processes: (i) the 
greasy or gummy film must be broken up, that the 
entangled dust and dirt may be set free; (2) the. dust 
must be removed by mechanical means. 

We will have occasion to use alkalis for cleaning and 
acids for removing stains and it will be well to consid- 
er what is meant by the terms, acid, alkali, and salt. 

An acid is a substance with an acid or sour taste 

An 

^^^^ and having the property of changing certain vegetable 
colors. A substance much used in testing for acids is 
litmus, a kind of fungus, giving a blue solution in 
water. Paper soaked in litmus solution and dried is 
known as test paper or litmus paper. It can be bought 
at any druggist's. This paper is turned red by the 
presence of any acid, even in the most minute quantity. 
An acid will cause effervescence with a carbonate like 
cooking soda or washing soda. 
^„ An alkali is a substance often having a soapy taste, 
Alkali ^ slippery feeling if strong, and the property of turn- 
ing red litmus, blue. 

Alkalies will neutralize the effects of acids. If an 
acid be added very carefully to an alkaline solution, 
there comes a point where the mixture will change the 
color of litmus in neither direction. The solution is 
neither acid nor alkaline, and is said to be neutral. 
If we make a weak solution of the acid sold at the 
drug stores as muriatic acid, and add to this very care- 
fully a weak solution of caustic soda, until the solu- 
tion is neutral, we shall find that the neutral solution 



CLEANING. 57 

will taste like table salt. In fact, we have made com- 
mon salt in this way. 

A chemical salt is a substance obtained by neiitraliz- ^ sait 
ing an acid with an alkali or otherwise — a substance 
that is usually neutral and will turn the color of neither 
red nor blue litmus paper. 

All acids contain the element hydrogen, which can 
often be driven out and replaced by a metal placed in 
the acid. If we drop a bit of zinc into some muriatic 
acid, tiny bubbles of hydrogen begin to escape. The 
zinc joins the remainder of the acid, making a 
new substance. This new substance is the metallic 
salt, called muriate (or chloride) of zinc. Muriatic 
acid is also called hydrochloric acid. Thus a salt re- 
sults from neutralizing an acid with a metal. If oxide 
of zinc, a white powder, has been used in place of the 
metal, the same salt, chloride of zinc, would have been 
made ; but no hydrogen gas would have come off, for 
the hydrogen of the acid would unite with oxygen of 
the oxide and form water. 

Grease or fats, called oils when liquid at ordinary Fats 
temperature, are chemical compounds made of carbon, ous 
oxygen, and hydrogen combined in many different 
ways, but all contain an ingredient of an acid nature 
known to the chemist as a fatty acid. The fatty acid 
base is combined with glycerine in the common fats. 

Strong alkaline substances will break up fats into 
their parts and combine with the fatty acid, thus 
making soap. 



58 CHEMISTRY OF THE HOUSEHOLD. 

Alkali '^^^ elements which form strong alkaHs are the 

Metals "alkali metals." The common elements of this group 

are sodium and potassium. There is also ammonium 

which is not an element, but a combination of nitrogen 

and hydrogen ; it acts, however, like an alkali metal. 

When an element unites with water in a certain way 
it is called a hydrate or hydroxide. The hydrate of 
ammonium — aqua ammonia or ammonia — is known as 
the ''Volatile alkali" because it evaporates so easily. 
It is valuable for use in all cleansing operations — in 
the kitchen, the laundry, the bath, in the washing of 
delicate fabrics, and in other cases where its property 
of evaporation, without leaving any residue to attack 
the fabric or to absorb anything from the air, is in- 
valuable. 

Caustic The hydrates of potassium and sodium are called 

^°n5 caustic potash and caustic soda, respectively, or the 

p*oTash caustic alkalis or "lyes" because they "burn" animal 

tissues. These combine readily with fats to form 

compounds which we call soaps. 

Most of the fats are soluble in turpentine, ether, 
chloroform, naphtha, or kerosene, and somewhat in 
alcohol. That is, the fats are dissolved unchanged, 
just as salt is taken up by water. These form solvents 
for greases more or less valuable according to con- 
ditions. 

If the housekeeper's problem were the simple one 
of removing the grease alone, she would solve it by the 
free use of one of the solvents or by some of the strong 



Soap 



CLEANING. 59 

alkalis. This is what the painter does when he is 
called to repaint or to refinish ; but the housewife 
wishes to preserve the finish or the fabric while she 
removes the dirt. She must, then, choose those ma- 
terials which will dissolve or unite with the grease 
without injury to the article cleaned. 

Soap is by all odds the safest and most useful 
cleaning agent. It is made from most of the common 
animal and vegetable fats and oils, as tallow, suet, lard, 
cotton seed oil and cocoanut oil, chemically combined 
with caustic soda or caustic potash. Castile soap is sup- 
posed to be made from olive oil. Rosin soap forms a 
part of all common yellow soap. It lessens the cost 
and makes a good soap for rough work. Silicate of 
soda is sometimes added to cheap soaps. It has some 
cleansing action, but must be regarded as an adulter- 
ant. 

Good soaps are nearly neutral substances because 
the alkali has been neutralized by the fatty acid. The 
coarser grades may contain more or less free alkali. 
All soaps are slightly decomposed when dissolved in 
water. The freed fatty acid produces the milkiness 
seen when a cake of soap is placed in perfectly pure 
water. 

The cleaning action of soaps consists chiefly in 
forming emulsions with oily or greasy substances. o^ soap 
Cream is an example of a very perfect emulsion. Its 
fat is in the shape of very finely divided globules and 
because of the whey which surrounds them, the cream 
can be mixed with a very large quantity of water and 



Action 



6o CHEMISTRY OF THE HOUSEHOLD. 

show no sign of greasiness. When the whey is sep^ 
arated as in churning, the globules of fat come together 
and butter is formed. An emulsion is not a true solu- 
tion, for the particles of fat can be separated by proper 
means from the liquid. 

The soap makes an emulsion with the oily or greasy 
substances holding the dirt, so that both may be 
washed away by the water. A certain proportion of 
free alkali in soap helps the action, but it has a cor- 
rosive effect on many materials. Soap will form 
emulsions with many other materials besides fats and 
oils ; so while water is a very general solvent, soap 
and water will take up many additional substances. 
Kinds The housekeeper may be familiar with two kinds of 
jf Soap gQ^p . i^aj.(j soaps and soft soaps. Caustic soda makes 
the hard soaps and caustic potash makes the soft 
soaps. 

Caustic potash is derived from wood ashes and a few 
generations ago soft soap was the only laundry soap 
used. Wood ashes were plenty when wood fires were 
universal. Soda-ash was at that time derived from 
sea weeds, and therefore uncommon inland. Early in 
the century a French manufacturer, Leblanc, dis- 
covered a process of making soda-ash from sodium 
chloride or common salt. This quite reversed the con- 
dition of the two alkalis, for now soda-ash is much 
more common, and the manufacture of soap on a large 
scale really began then. Soda-ash is now the cheapest 
form of alkali. Caustic soda is made from soda-ash. 



CLEANING. 6i 

The terms, soda-ash, and pot-ash have been used ; soda-Ash 
these substances in chemical terms are respectively 
the carbonate of sodium and the carbonate of potas- 
sium. They are chemical compounds made up of car- 
bonic acid and two metals — sodium and potassium. 
When the carbon dioxide, which we have seen is 
formed by the combustion of carbon, is added to water, 
carbonic acid results. This is a very weak acid and 
when it is combined with the very strongly alkaline 
elements, sodium or potassium, the result is an alka- 
line substance. Soda-ash and potash (sometimes called 
pearl-ash) are called alkalis, but they are not nearly 
so powerful as the hydrates of sodium and potassium 
which are commonly called caustic soda and caustic 
potash. 

When soda-ash, which is a white powder, is dis- washing 
solved in hot water and the solution is cooled, crystals 
of the common washing soda are formed. This sub- 
stance is also called ''sal soda" and "soda crystals." 
The crystals contain about 65 per cent of water and 
when exposed to the air, lose some of this water and 
crumble to the white powder, soda-ash. The powder 
is, therefore, stronger than the original crystals. 

Washing soda should never be used in a solid form, 
but should be dissolved in a separate dish, and the 
solution used with judgment. A satisfactory amount 
is about two ounces of the dry soda to a large tub of 
water, and well dissolved before the clothes are put in. 
Nearly all of the "washing compounds" on the market 



Soda 



62 



CHEMISTRY OF THE HOUSEHOLD. 



Borax 



Hard 
Water 



Temporary- 
Hardness 



Permanent 
Hardness 



depend upon the washing soda for their efficiency, and 
sometimes they contain nothing else. 

Borax is a useful alkali, milder than washing soda, 
but effective as a cleaner, disinfectant, and bleacher. 
It is more expensive than either of the others de- 
scribed, and because of its weaker alkaline action, more 
of it must be used to produce a given result. It is 
much less irritating to the skin and less injurious to 
fabrics than soda, so for some uses its additional cost 
may be justified. Caustic potash or *'lye" is too strong 
an alkali to use on fabrics, but is valuable to put down 
the kitchen sink drain to free it from grease. The 
soap made in the drain will be washed out by water. 
Solid washing soda may be used for the same pur- 
pose. 

In the laundry the composition of water is im- 
portant. Water for domestic use is either hard or soft, 
according as it contains a greater or less quantity of 
certain soluble salts — usually compounds of lime or 
magnesia, which have been taken up by the water while 
passing through the soil. 

When the hardness is caused by calcium carbonate 
(carbonate of lime) it is called ''temporary" hardness, 
because it may be overcome by boiling. The excess of 
carbon dioxide is driven off and the carbonate of lime 
separates out. The same separation is accomplished 
by the addition of sal soda, borax, or ammonia. 

When the hardness is due to the sulphates and 
chlorides of magnesia or lime, it cannot be removed 



CLEANING. 



63 



by boiling. It is then known as "permanent" hard- 
ness. Pubhc water supphes are sometimes softened 
before delivery to the consumer by the addition of 
slaked lime, which absorbs the carbon dioxide, and 
the previously dissolved carbonate separates out. 

Soft water is needed in laundry work both for 
cleanness and economy, and water not naturally soft 
should be softened by boiling or by the addition of the 
before mentioned substances. 

When soap is added to the hard water, it is decom- 
posed by the water, and the new compound formed by 
the union of the lime and magnesia with the fatty acid 
of the soap is insoluble, and therefore settles upon any 
article with which it comes in contact. Until all the 
lime has been taken out, there will be no action be- 
tween the soap and the dirt. Therefore, large quanti- 
ties of soap must be wasted. It has been estimated that 
each grain of carbonate of lime per gallon causes an 
increased expenditure of two ounces of soap per 100 
gallons,, and that the increased expense for soap in a 
household of five persons where such hard water is 
used might amount to five or ten dollars yearly. 

This ''lime soap," although insoluble in water, will 
dissolve readily in kerosene or naphtha, for which rea- 
son, kerosene will be found very effective for cleaning 
bowls or the bath tub when the surface has become 
coated from the use of hard water and soap. 

Hard waters produce certain undesirable effects in 
cooking processes. The cooking of beans and similar 



Soap and 
Hard Water 



Cooking with 
Hard Water 



64 CHEMISTRY OF THE HOUSEHOLD. 

vegetables should soften the cellulose and break up 
the compact grains of starch. It is difficult to cook 
vegetables in hard water, for the legumin of the vegeta- 
ble forms an insoluble compound with the lime or 
magnesia of the water, and the cellulose is softened 
with great difficulty. Hard water does not readily 
extract the flavor from tea and coffee, and therefore 
much more of either must be used to get the desired 
strength. 

Dish During this discussion of cleansing agents, let us 

Washing hope that the breakfast dishes have been soaking in 
water, after having carefully scraped or "scrapped" 
so as to save soap in washing and to keep the water 
as clean as possible. Plenty of hot water and soap 
with clean, dry towels is the secret of quick and easy 
work. If the hard water is used, it may be softened 
for the soap is doing no good unless there is a strong 
suds. 

To save the appearance of the hands, use a good 
white soap, free from alkali, and soften the water with 
borax. 

Glass, silver ware, china and kitchen ware take their 
turn. All should be rinsed in hot water to remove 
the soap and heat the dishes so that they will drain 
nearly dry and thus make wiping easy. In the dish 
washing machine used in large hotels and restaurants, 
the dishes are simply washed with soapy water and 
rinsed in very hot water while in such a position that 



CLEANING. 



6S 



they drain perfectly. They dry completely and re- 
quire no wiping. Fig. i6. 




^na^f'ixa^^^^^^mwitsiiew/ftaiMMf'^^^^^i^miissmKsei^ 



Fig. 16. 



Dish Washing Machine Used in Large Hotels and 
Restaurants. 



Experiment. Wash a plate and dip it in very hot 
water, then place it so that all parts will drain. Ob- 
serve if it dries completely. See if you can wash the 
dishes in this manner with very little wiping and if 
time would thus be saved. 



66 



CHEMISTRY OP THE HOUSEHOLD. 



structure 
of Fibres 



Cotton 



Wool 



Linen 



CHEMISTRY OF THE LAUNDRY 

If the morning happens to be Monday, the washing 
is probably in progress in the average American fam- 
ily. The mistress should understand the chemical 
principles involved and every detail of the work, in 
order that the best results may be secured, and that 
the clothes may not be harmed. 

The fibres of cotton, silk, and wool vary greatly 
in their structure and a knowledge of this structure 
as shown under the microscope, may guide to proper 
methods of treatment. Fig. 17. 

The fibres of cotton, though tubular, become much 
flattened during the process of manufacture, and under 
the microscope, show a characteristic twist, with the 
ends gradually tapering to a point. It is this twist, 
which makes them capable of being made into a firm, 
hard thread. 

The wool fibre, like human hair, is marked by trans- 
verse divisions, and these divisions are serrated. These 
teeth become curled, knotted or tangled together by 
rubbing, by very hot water, or by strong alkalies. 
This causes shrinking, which should be prevented. 
When the two fibres are mixed, there is less opportun- 
ity for the little teeth to become entangled and there- 
fore there is less shrinkage. 

Linen fibres are much like cotton, with slight notches 
or joints along the walls. These notches serve to hold 
the fibres closely together, and enable them to be 
felted to form paper. Linen, then, will shrink, though 




■.03 

a 

QJ 



H 





> 






o 




[H 






K 






Q 


o 




2:; 


-i-> 




p 


o 




<1 






hJ 


W 




o 


•- 




1— 1 


a 




PS 


OS 




H 


to 


w 


1^ 


o 


a 

o 


K 


o 


V 








1^ H 






^ 


c 










^ 


w 




s 


CI) 




o 


hr 




o 


n 




K 


'tj 




t>. 


^ 




*- 






P 


s 




"C CS 




Oj 






+J 






CO 

o 


a 




ffi 


^ 



(3 



THE LAUNDRY. 



67 



not so much as wool, for the fibres are more wiry and 
the teeth much shorter. 

Silk fibres are perfectly smooth and when rubbed, 
simply slide over each other. This produces a slight 
shrinkage in the width of woven fabrics. 

Cotton and wool differ 
greatly in their resistance 
to the treatment of chemi- 
cals. Cotton is very little 
affected by a solution of the 
alkalies, when the cloth is 
well rinsed. If the alkali is 
not removed completely, 
however, it becomes very 
concentrated when the cloth 
dries, and as it generally 
acts for a long time, the 
fibre may be weakened or 
''tendered." 

Cold dilute solutions of the acids have no very great 
effect on cotton, provided always that they are com- 
pletely washed out. Strong or hot solutions of acids 
have a very decided deleterious action, and even a very 
minute quantity of acid dried on the goods tenders the 
fibre badly. 

Wool resists the acids well, but is much harmed 
by the action of the alkalies. A warm solution of caus- 
tic soda or caustic potash will dissolve wool quickly 
and completely. The carbonates, like washing soda, 




C D 

Textile Fibres Much 
Magnified, 
a, Wool; b, Mohair; C, Cot- 
ton; d, Silk; e, Linen. 



Silk 



Chemical 
Action 
on Fibres 




o 



o 



o 
o 



o 

o 



o 
o 



o 

o 




A MECHANICAL WASHING DEVICE 

Made to fit in the bottom of a wash boiler. The formation of 

steam forces the hot, soapy water up the spouts, 

over and through the clothes. 




SPECIAL IRON HEATER 

A gas saver. Made as an attachment to a gas stove and as a 

separate stove on legs. 



THE LAUNDRY. 69 

most needed. The water should be well softened, and 
a very little extra washing soda solution may be 
added. The soaking loosens the dirt and saves much 
rubbing and hence wear on the clothes. It is probable 
that the cleansing wears out the articles which make 
up the weekly wash more than the actual use they re- 
ceive. 

After washing the clothes, they may be wrung out Boiling 
and put into a boiler of cold water, which is then 
heated and boiled briskly for a little while. Whether 
to boil, or not to boil the clothes depends largely 
upon the purity of the materials used. If there is any 
iron in the water, or elsewhere, it is sure to be de- 
posited on the goods, thus producing yellowness. Soap 
may be added to the clothes in the boiler, or borax 
may be used, allowing a tablespoonful to every gallon 
of water. The borax serves as a bleacher and as an 
aid in the disinfection of the clothes. One great ad- 
vantage of boiling is the additional disinfection which 
this insures. 

After washing, the clothes should be thoroughly Ringing 
rinsed. They cannot be clean otherwise and proper 
rinsing is essential to successful washing. The more 
thoroughly the wash water is removed between rins- 
ings, the less number of rinsings will be required to 
give the same results. 

Bluing is frequently added to the last rinsing water 
to counteract, or cover up, any yellowness. A light 
blue appears to the eye whiter than a light yellow. 



Bluing 



70 CHEMISTRY OF THE HOUSEHOLD. 

The color is, however, gray in comparison with white. 
Most of the Hquid bkiing now on the market contains 
Prussian Blue, a compound of iron. This compound 
is decomposed by soap and alkalies, when the goods 
are next washed, making a slight yellow stain of iron 
on the cloth. Frequent repetitions of this action may 
give a distinctly yellow shade to the white goods. The 
indigo blue used a generation or more ago did not 
have this objection. It is said that white goods which 
have never been blued, never require bluing. 

stains Stains and all special deposits should be removed 

before the goods are treated with soap or soda, as 
these frequently set the stains. Hot water will spread 
any grease and also set many stains-, so the clothes 
when not soaked, should be wet thoroughly in cold 
or luke-warm water before washing. 

Washing Colorcd goods and prints require more delicate treat- 
^ Goods ment than white goods. If they are soaked, the water 
should be cold and contain very little soap and no 
soda. Only dissolved soap should be used in wash- 
ing them, and this should be of good quality, free 
from alkali. They should be dried with the wrong 
side out aftd in the shade, for direct sunlight fades 
colors about twenty times as much as reflected light. 

Washing All wool goods rcquirc the greatest care in wash- 

wooiens .^^^ ^^^^ difl'erent waters used should be of the same 

temperature and never too hot to be borne comfortably 

by the hand. 




Size, 



GAS-HEATED IRONING MACHINE 
37. inches. Price, $40.00. With Electric Motor, $100 




SMALL HEATED HAND MANGLE 
Size, 24 inches. Price, $32.00 




A COLD MANGLE 
Price, $6.75 




GENERAL, ELECTRIC COM- 
PANY FLAT IRON 
ON STAND 
Price, $3.50 to $5.00 




GASOLINE OR ALCOHOL 
* IRON 
Price, $5.00 



Soap 
Solution 



THE LAUNDRY. 71 

The soap used should be in the form of a thin soap 
solution. No soap should be rubbed on the fabric and 
only a good, white soap, free from rosin, is allow- 
able. Make each water slightly soapy and leave a 
very little in the fabric at the end, to furnish a 
dressing as nearly like the original as possible. 

Many persons prefer ammonia or borax in place 
of the soap. For pure white flannel, borax gives the 
best satisfaction on account of its bleaching quality. 
Whatever alkali is chosen, care should be exercised in 
the quantity taken. Only enough should be used to 
make the water very soft. 

The fibres of wool collect much dust upon their srushing 
tooth-like projections and this should be thoroughly 
brushed or shaken off before the fabric is put into 
water. All friction should be by squeezing, not by 
rubbing. Wool should not be wrung by hand. Either 
run the fabric smoothly through a wringer or squeeze 
the water out, that the fibres may not be twisted. 
Wool may be well dried by rolling the article tightly 
in a thick dry towel or sheet and squeezing the whole 
till all moisture is absorbed. Wool should not be al- 
lowed io freeze, for the teeth will become knotted 
and hard. Above all, the drying should be accom- 
plished quickly, and in short, the les? time that is 
taken in washing, rinsing, and drying, the less will 
be the shrinkage and the better will be the result. 



Woolens 



starching 



Cooked 
Starch 



Uncooked 
Starch 



72 CHEMISTRY OF THE HOUSEHOLD 

Some of the clothes are starched. This in addition 
to making them stiffer and giving them a better ap- 
pearance helps to keep them clean longer. Practically 
all the household starch on the market is corn starch, 
although in the textile industries and large laundries, 
wheat, potato and rice starches are used. Corn starch 
has the greatest stiffening effect, but wheat starch and 
rice starch penetrate better and give a more flexible 
finish. 

To make cooked starch for ordinary work, wet ^ 
cup with y^ cup of water and pour on one quart of 
boiling water. Boil thoroughly till clear. Use double 
the quantity of starch for stiff starching. Borax may 
be added — ^ to i level tablespoon to a quart — to in- 
crease the gloss and penetrability and to prevent the 
iron from sticking. Lard, wax or paraffine is some- 
times cooked with the starch for the same purpose — yi 
tablespoon to a quart. 

For very stiff starching, as for collars, the thick 
paste should be rubbed thoroughly into the goods and 
the excess wiped off with a damp cloth, after which the 
goods is dried before a fire. 

The prepared starches, to be used cold, contain 
borax. This may just as well be added to cheaper 
preparations. As the uncooked starch depends upon 
the heat of the iron to swell and stiffen it, a hotter 
iron is required than with boiled starch. 

For producing an ecru shade in curtains, coffee is 
sometimes added in quantity to give the desired color. 
A solution of gum arable is sometimes used to stiffen 









A METHOD OF FOLDING DRESSES, SHIRTS AND SHEETS 
OR TABLE CLOTHS 



/ 



fr V ^ • \\\\ irrfV' 




.liaLu 






"/ C? 



nVi'i'n^TU /■iVrVl^1-i••y^^) ^ 'nine •.,,-!. ^^ ^■•n|'vrM,pvi^ 

k:-i.v:.C;:V,j kii^;v•:;^:^^ii bii^^^Ii-^vA l^^j^^^,.^ 




\ 





METHOD OF FOLDING UNDERCLOTHES 



ORDER OF IRONING 

Night Dresses: 

1 — embroidery, 2 — sleeves, 3 — yoke, 4 — body. 
Drawers: 

1 — trimming, 2 — tucks, 3 — body, 4 — band. 
Skirts: 

1— ruffle, 2— hem, 3— body. 
Shirt Waists: 

1 — cuff, 2 — collar band, 3 — sleeves, 4 — yoke, 5 — back, 6 — front. 

(From "The Laundry," by Flora Rose; Bulletin of tbe Cornell Reading 
Course for Farmers' Wives, Ithaca, N. Y.) 



THE LAUNDRY. 



1Z 



dark colored clothes which would show the white 
color of the starch. 



THE REMOVAL OF STAIN 

Whenever possible, stains should be removed when 
fresh. If the staining substance is allowed to dry on 
the cloth, its removal is always more difficult, and 
sometimes a neglected spot or stain cannot be removed 
without damage to the cloth. 

The nature of the spot must be known before the 
best substance to dissolve and remove it can be chosen. 
To remove grease spots, solvents of grease should 
be chosen, though w^e may remove such spots some- 
times by causing the grease to form an emulsion with 
soap and thus be removed, or the grease may be made 
into a soap with ammonia or washing soda and thus 
dissolved and removed in water. The first of the three 
methods is, as a rule, the best. Grease will dissolve 
readily in benzine, naphtha, gasoline, kerosene, ether, 
and chloroform and somewhat in turpentine and hot 
alcohol. Ether and chloroform are the best solvents, 
but they are more expensive and not much more ef- 
fective than naphtha. 

Caution! All of the solvents for grease are in- 
flammable and some are explosive, so that they should 
never be used near a fire or light. Work with them 
should be done in the day time and preferably out of 
doors. 



Grease 
Spots 



Precautions 



A.bsorbents 



74 CHEMISTRY OF THE HOUSEHOLD. 

In applying any of these solvents to grease spots 
in fabrics, a cloth should be placed underneath the 
stain to absorb the excess of liquid containing the 
dissolved grease. The spot should be rubbed from 
the outside towards the center until dry. This will 
tend to distribute the solvent and prevent the formation 
of a ring where the liquid stops. It is well to apply 
the solvent on the wrong side of the fabric. Old spots 
of any kind may require long treatment. For this a 
little lard may be rubbed into the spot and left for 
some time, then the whole may be dissolved by naphtha 
or washed out with soap or ammonia. 

Spots of grease on carpet or heavy material may be 
treated with absorbents. Heat will assist by melting 
the grease. Fresh grease spots may often be removed 
by placing over the spot a clean piece of blotting 
paper and pressing the spot with a warm iron. French 
chalk or whiting may be moistened with naphtha and 
spread over the spot. When all is dry, brush ofif the 
absorbent. The absorption method may be used in 
many other cases, moistening with cleansing agent 
which will not harm the material treated. 

Biuin Bluing spots may frequently be removed by soak- 

stains -^^g -j^ strong ammonia water. Alcohol or ammonia 
will remove grass stains, and an old remedy is to smear 
the stains with molasses before the article goes into 
the wash. The acids in the molasses seem to have 
the desired effect on the grass stains. 



STAINS. 



75 



Fresh stains of cofifee, tea or frnit may be removed 
by hot water. Stretch the stained part over an earth- 
en dish and pour boiling water upon the stain until it 
disappears. It is some times better to sprinkle the 
stain with borax and soak in cold water before ap- 
plying the hot water. Old, neglected stains of coffee, 
fruits, cocoa, etc., will have to be treated with some 
bleaching agent. In many cases, it is not possible to 
remove them without severely damaging the cloth. 

Mildew causes a spot of a totally different char- 
acter from any we have considered. It is a true mold, 
and like all plants, requires warmth and moisture for 
its growth. When this necessary moisture is furnished 
by any cloth in a warm place, the mildew grows upon 
the fibres. During the first stage of its growth, the 
mold may be removed, but in time, it destroys the 
fibres. 

Strong soapsuds, a layer of soft soap, and pulver- 
ized chalk, or one of chalk and salt, are all effective 
if, in addition, the moistened cloth be subjected to 
strong sunlight, which kills the plant and bleaches the 
fibres. Bleaching powder or Javelle water may be 
tried in cases of advanced growth, but success cannot 
be assured. 

Some of the animal and vegetable oils may be taken 
out by soap and cold water or dissolved in naphtha, 
chloroform, ether, etc. Mineral oil stains are not sol- 
uble in anv alkaline or acid solutions. Kerosene will 



Coffee and 
Fruit Stains 



Mildew 



Vaseline Staini 



76 



CHEMISTRY OF THE HOUSEHOLD. 



Paint 



Ink Spots 



Indelible 
Ink 



evaporate in time. Vaseline stains should be soaked 
in kerosene before water and soap touch them. 

Paints consist mainly of oils and some colored earth. 
Spots of paint, then, must be treated with something 
that will take out the oil, leaving the insoluble color- 
ing matter to be brushed off. Turpentine is most 
generally useful. 

Spots of varnish or pitch may be dissolved by the 
use of the same solvents as paint. Alcohol is also one 
of the best solvents here. 

Spots made by food substances are greasy, sugary, 
or acid in their nature. Whatever takes out the grease 
will generally remove the substance united with it, 
as the blood in meat juices. Sugar is dissolved by hot 
water, so sticky spots are best removed with this. 

Ink spots are perhaps the worst that can be encoun- 
tered, because of the great uncertainty of the composi- 
tion of inks of the present day. When the character 
of an enemy is known, it is a comparatively simple 
matter to choose the weapons to be used against him, 
but an unknown enemy must be experimented upon 
and conquest is uncertain. 

Indelible inks formerly owed their permanence to 
silver nitrate. Now many are made from aniline black 
solutions and are scarcely aftected by any chemicals. 
The silver nitrate inks become dark in the sun by a 
photographic process. Many silver salts, and some 
salts of other metals, change in color in a bright light. 



Ink 



STAINS. 7T 

Silver nitrate inks may be removed by bleaching 
powder solutions. The chlorine in this replaces the 
nitric acid forming white silver chloride. This will 
darken if not at once removed, but will dissolve in 
strong ammonia water or a solution of hyposulphite of 
soda. This last salt, much used by photographers, 
commonly called "hypo," will often dissolve the stain of 
indelible ink without the use of the bleaching fluid 
and is less harmful to the fibres. Some inks contain 
carbon in the form of lamp black which is not affected 
by any chemicals which can be used. 

The old fashioned black ink is a compound called writing 
the gallo-tannate of iron. It is made by adding a solu- 
tion of sulphate of iron to a water solution of nut 
galls. A little gum solution is added to make the ink 
of better consistency. This kind of ink is removed 
by the addition of a warm solution of oxalic acid 
or muriatic acid drop by drop, and this finally well 
rinsed out. Of course some materials will be injured 
by the acids, so this method must be used with cau- 
tion. Lemon juice and salt will sometimes remove 
the spot and is safe. Cover the spot with salt, wet with 
lemon juice, and spread in the sun. Bleaching powder 
solution and acid will frequently destroy any ink stain 
of long standing which acids alone will not affect. 

Some ink stains are removed when fresh by clear, 
cold, or tepid water — skimmed milk is safe and often 
effective. If the stain is allowed to soak in the milk 



Carpets 



78 CHEMISTRY OF THE HOUSEHOLD. 

until the milk sours, the result is often better. Some- 
times the ink will dissolve out if a piece of ice is laid 
on the spot and blotting paper under it. The blotting 
paper absorbs the water and should be often changed. 
Ink on Ink on heavy materials like carpets and draperies 

may be treated with some absorbent to keep the ink 
from spreading. Bits of blotting paper, cotton batting, 
meal, flour, sawdust, etc., may be used and removed 
as long as any ink is absorbed, then go over the spot 
repeatedly with a lemon freshly cut, and finally rinse 
with cold or tepid water. If an ink stain has worked 
through varnish into the wood, turpentine will usually 
remove the spot. 

Of late colored inks are generally prepared from 
aniline colors. These are made from substances pro- 
duced in the distillation of coal tar. The colors are 
soluble in water, and by dissolving them and adding 
to the mixture some thickening substance, different 
colored inks are produced. They are rather difficult 
to remove successfully, but bleaching powder solution 
will frequently destroy them. 
Iron The red iron-Fust spots must be treated with acid. 

These are the results of oxidation — the union of the 
oxygen of the air with the iron in the presence of mois- 
ture. The oxide formed is deposited upon the fabric 
which furnishes the moisture. Ordinary "tin" uten- 
sils are made from iron coated with tin, which soon 
wears ofif, so no moist fabric should be left long in tin 
unless the surface is entire. 



Colored 
Inks 



Rust 



STAINS. 



79 



tron-nist Is, then, an insoluble oxide of iron. The 
chloride of iron is soluble and so hydrochloric acid is 
used to remove the rust. The best method of apply- 
ing the acid is as follows : Fill an earthen dish two- 
thirds full of hot water and stretch the stained cloth 
over this. Have near two other dishes with clear 
water in one and ammonia water in the other. The 
steam from the hot water will furnish the heat and 
moisture favorable for chemical action. Drop a little 
hydrochloric (muriatic) acid on the stain with a medi- 



Removins 
Rust 




FIG. 19. REMOVING IRON RUST STAIN. 

cine dropper. Fig. 19. Let it act a moment, then 
lower the cloth into the hot water. Repeat till the 
stain disappears. RJnse carefully in the clear water 
and, finally, immerse in the ammonia water, that any 
excess of acid may be neutralized and the fabric pro- 
tected. 

Salt and lemon juice are often sufficient for a slight 
stain, probably because a little hydrochloric acid is 
formed from their union. 



Salt and 
Lemon Juice 



8o CHEMISTRY OF THE HOUSEHOLD. 

Ink stains on colored goods are often impossible 
to take out without also removing part of the dye. The 
ink must be washed out in cold water before it dries ; 
any slight stain remaining can, perhaps, be removed 
with a weak acid like lemon juice without harming 
the color. 

BLEACHING 

When the clothes are washed, the mistress likes 
to have them hang out of doors where the air and 
sunshine can dry them. She is glad when the white 
articles can be spread on the grass, knowing that they 
will be made whiter by Nature's bleaching agent. 
The sunlight is the chief agent in this bleaching and the 
articles are laid flat on the grass so that the rays of 
light will strike in a more perpendicular direction. 
There are also other devices for bleaching, among 
which are the fumes of burning sulphur, chloride of 
lime (bleaching powder) and Javelle water. 

Originally all bleaching of linen and cotton was 
done out of doors by the action of oxygen, water, and 
sunlight. In these days of great factories, this process 
is impossible for lack of space ; but various artificial 
bleaching stuffs have been discovered whose action is 
satisfactory if skilfully used. 
Bleaching Chloriuc is a gas which has remarkable readiness to 

combine with other bodies. It is even more energetic 
than oxygen. By its action upon them, chlorine de- 
stroys the greater number of coloring substances. Be- 



BLEACHING, 



8i 



cause of its liarmful action upon the human body, 
chlorine gas itself cannot be used in factories or in the 
household, but the compound which chlorine forms 
with lime (oxide of calcium) known as chloride of 
lime or bleaching powder, is safe and effective. 

The principal coloring matters are composed chiefly 
of the elements carbon and hydrogen and some of the 
metals = If a substance which makes new combination 
with the elements present is brought in contact with 
these colors, the new compounds thus produced may 
be colorless. The element chlorine does just this. 
It can be set free from chloride of lime by weak acids, 
and will dissolve very readily in water when so set 
free. By dipping colored cloth into a weak solution 
of chloride of lime and acid, many colors and stains 
are at once destroyed. But the energy of the chlorine 
is not stopped by this process. Having destroyed 
the color, the bleaching powder attacks the fibres of 
the goods, unles.: the cloth is at once placed in some 
solution which can neutralize the bleaching powder. 
There are several such easily obtained and used. The 
use of bleaching powder in the household is frequently 
of dubious success for lack of this precaution. Am- 
monia water will perform this action satisfactorily, 
since the harmless soluble salt, ammonium chloride, 
is formed ; hypo-sulphite of soda is also effective. 

Chloride of lime loses strength rapidly if exposed 
in an open vessel. It absorbs water and carbon di- 



Action of 
Chlorine 



Chloride 
of Lime 



82 CHEMISTRY OF THE HOUSEHOLD. 

oxMe from the air, grows damp and the chlorine gas 
escapes. 

In using bleaching powder, mix one or two tea- 
spoonfuls with a pint of cold water in an earthen- 
ware dish. The effective part of the powder will be 
dissolved, so let the mixture settle, or strain off the 
liquid through a cloth. Add a little vinegar or a few 
drops of acetic acid to the nearly clear solution and 
use at once. 

javeiie Javcllc watcr is also used as a bleaching agent. It is 
Water ^^^^ jjj^^ blcaching powder, except that soda replaces 
the lime. It is prepared by dissolving one pound of 
washing soda in a quart of hot water and adding one 
quarter of a pound of chloride of lime also dissolved 
in a quart of hot water. Let the mixture settle, pour 
off the clear liquid and bottle it for use. It will keep 
for some time. The dregs may be used to scour 
the kitchen floor or to disinfect waste pipes. This is 
very useful in removing stains on white cloth, but 
the addition of some solution to neutralize the action 
is always necessary, just as with bleaching powder. 
The best substance to use for this is hypo-sulphite of 
soda, the "hypo" used in photography, which is quite 
harmless to the cloth. 

Sulphur Chlorine cannot be used in bleaching fabrics of ani- 

Bieiching '^^^^ ^hvQ such as wool and silk ; it leaves them yellow 

rather than white. For these the fumes of burning 

sulphur, or these fumes dissolved in water must be 



BLEACHING. 



83 



used. No special means of destroying the excess of 
sulphur fumes i's required. These fumes are a com- 
pound of sulphur and the oxygen of the air and famil- 
iar to every one, in the acid fumes from a burning 
"sulphur match." The article to be bleached must be 
wet, and then hung in some enclosed space above a 
piece of burning sulphur. The sulphur candles, to be 
had at any druggist's, are convenient for this use. 
Fig. 20. The fumes have great affinity for oxygen, 
that is, unite with it easily, and take it from the color- 
ing stuffs, converting them into colorless ones. This 
method of bleaching is sometimes not permanent. 




FIG. 20. A SULPHUR CANDLE. 



These fumes of sulphur are often used to disinfect 
rooms where there has been sickness. Its power in 
this respect is far less than is generally supposed how- 
ever, and much larger quantities of the gas are re- 
quired for thorough work than are commonly used. 
Chlorine gas is an excellent disinfectant, but is dan- 
gerous to use because of its irritating effect upon the 
throat and lungs. The use of ''chloride of lime" as a 
disinfectant depends upon the fact that chlorine slowly 



84 CHEMISTRY OF THE HOUSEHOLD. 

escapes from this substance when it is exposed to the 
air. 

Hydrogen Another bleaching agent of growing importance 

Peroxide -^ pej-Qxide of hydrogcn. Water is a compound made 
up of one-third oxygen and two-thirds hydrogen. Un- 
der certain conditions, a compound half oxygen and 
half hydrogen may be prepared. This is not very 
permanent as the extra oxygen slowly escapes. This 
extra oxygen has great power as a decolorizer. The 
peroxide is a liquid much like water in appearance 
and is used in bleaching hair, feathers, and ivory. It 
is the safest bleaching agent for the housekeeper to 
work with and may be used on wool and silk as well 
as cotton and linen. 

CLEANING WOODWORK 

In the interior of the house woods are seldom used 
in their natural state. The surface is covered with 
two or more coatings of paint, varnish, etc., which 
add to the wood durability or beauty. The cleaning 
processes are applied to the last coat of finish and 
must not injure this. 

Soft woods are finished with paint, stain, oil, shel- 
lac, varnish, or with two or more of these combined ; 
hardwoods with any of these, and in addition, wax, or 
wax with turpentine, or both with oil. 
A:i^-:ie3 AH these surfaces, except those finished with wax, 

may be cleaned with a weak solution of soap or am- 
monia, but the continuous use of any alkali may im- 



in Cleaning 



CLEANING. 85 

pair and finally remove the polish. Refinishing will 
then be necessary. Waxed surfaces are turned dark 
by water. Finished surfaces should never be scoured 
nor cleaned with strong alkalies, like sal-soda, orpotash 
soaps. Scouring with these strong alkalies will break 
the paint or varnish and in this way destroy the finish. 

A few drops of kerosene or turpentine on a soft Kerosene 
cloth may be used to clean all polished surfaces. The 
latter cleans them more perfectly and evaporates read- 
ily ; the former is cheaper, safer, because its vapor is 
not so inflammable as that of turpentine, and it pol- 
ishes a little while it cleans ; but it evaporates so 
slowly that the surface must be rubbed dry each time, 
or the ^ust will be collected and retained. The harder 
the rubbing, the higher the polish. 

Outside the kitchen, the woodwork of the house sel- 
dom needs scrubbing. The greasy layer is readily 
dissolved by weak alkaline solutions, by kerosene or 
turpentine, while the imbedded dust is wiped away by 
the cloth. Polished surfaces keep clean longest. If the 
finish be removed or broken by deep scratches, the 
wood itself absorbs the grease and dust, and the stain 
may have to be scraped out. 

CLEANING METALS 

Most metals may be washed without harm in a hot 
alakline solution or wiped with a little kerosene. 
Stoves and iron sinks may be scoured with the coarser 
materials like ashes, emery or pumice ; but copper, pol- 



Tarnish 



86 CHEMISTRY OF THE HOUSEHOLD. 

ished steel, or the soft metals, tin, silver, and alumi- 
num require a fine powder that they may not be 
scratched or worn away too rapidly. Metal bathtubs 
may be kept clean and bright with whiting and am- 
monia, if rinsed with boiling hot water and wiped dry 
with soft flannel or chamois. 

Porcelain or soapstone may be washed like metal 
or scoured with any fine material. 

The special deposits on metals are caused by the 
oxygen and moisture of the air, by the presence of 
other gases in the house, or by acids or corroding 
liquids. Such deposits come under the general head 
of tarnish. 

The metals, or their compounds, in common use 
are silver, copper and brass, iron and steel, tin, zinc 
and nickel. Aluminum is rapidly taking a prominent 
place in the manufacture of household utensils. 

There is little trouble with the general greasy film 
or with the special deposits on articles in daily use, if 
they are washed in hot water and soap, rinsed well and 
wiped dry each time. Yet certain articles of food act 
upon the metal of tableware and cooking utensils, 
forming true chemical salts. 

The salts of silver are usually dark colored and 
Sulphide insoluble in water or in any alkaline liquid which will 
not also dissolve the silver. Whether found in the 
products of combustion, in food, as eggs, in the paper 
or cloth used for wrapping, in the rubber band of a 
fruit jar, or the rubber elastic which may be near the 



Silver 



METALS. 



87 



silver, sulphur forms with silver a grayish black com- 
pound—a sulphide of silver. All the silver sulphides 
are insoluble in water. Rub such tarnished articles, 
before washing, with common salt. By replacement, 
silver chloride, a white chemical salt, is formed, which 
is soluble in ammonia. If the article be not washed in 
ammonia it will soon turn dark again. With an old or 
deep stain of silver sulphide friction must be used. 

The analysis of many samples of silver polish, 
showed them to be made up of either precipitated 
chalk, diatomaceous earth or fine sand. In using them, 
it is necessary to be careful in regard to the fineness 
of material since a few coarse grains will scratch the 
coating of soft silver. In former times the housewife 
bought a pound of whiting for fifteen cents, sifted it 
through fine cloth, or, mixing it with water, floated off 
the finer portion, and obtained in this way, twelve 
ounces of the same material for three ounces of which 
the modern housewife pays twenty-five cents or even 
more, when she buys it ''by the box." 

The whiting may be made into a paste with ammonia 
or alcohol, the article coated with this and left till the 
liquid has evaporated. Then the powder should be 
rubbed off with soft tissue paper or soft cotton cloth, 
and polished with chamois. 

The presence of water always favors chemical 
change. Therefore iron and steel rapidly oxidize in 
damp air or in the presence of moisture. All metallic 
articles may be protected from such action by a thin 



Silver 
Polish 



Whiting 



88 CHEMISTRY OF THE HOUSEHOLD. 

oily coating. Iron and steel articles not in use may be 
covered with a thin layer of vaseline. 

Rust can be removed from iron or steel by kerosene, 
if not too deep. 

The tarnish on brass or copper will dissolve in am- 
monia water, but the objects tarnish again more quick- 
ly than if polished by friction. 



TEST QUESTIONS 

The following questions constitute the "written reci- 
tation" which the regular members of the A. S. H. E. 
answer ip. writing and send in for the correction and 
comment of the instructor. They are intended to 
emphasize and fix in the memory the most important 
points in the lesson. 



CHEMISTRY OF THE HOUSEHOLD. 

PART II. 



Read Carefully. Place your name and address on the first 
sheet of the test. Use a light grade of paper and write on one 
side of the sheet only. Do not copy answers from the lesson 
paper. Use your own words, so that your instructor may know 
that you understand the subject. Read the lesson paper a num- 
ber of times before attempting to answer the questions. 



1. Name all the substances you .can think of which 

are not soluble in water and are soluble in naph- 
tha or benzine. 

2. Does sugar neutrahze acid chemically? Why? 

3. Hovv^ is soap made? What is the difference be- 

tween hard and soft soap? 

4. What is "hard" water? How does it act with 

soap? How is it softened? 

5. Explain how "bluing" may make white clothes 

yellow. 

6. Why remove stains when fresh? Why before 

washing ? 

7. Why is there danger in using naphtha, benzine, 

and to some extent alcohol near a light ? 
80 How do cotton and woolen differ in the effect of 
acids and alkalies upon them? 



CHEMISTRY OF T^JE HOUSEHOLD 

9. What precautions must be taken in bleaching or 
removing stains with chloride of lime solution 
or with Javelle water? 

10. Give a good method of starching and ironing 

clothes. 

11. If possible, try to remove some stain by a method 

given in this lesson and tell of the results. 

12. Describe a good method of washing woolens. 

13. Why does the drying of a little acid or alkali on a 

fabric have a very disastrous effect? 

14. What is your method of washing dishes ? 

15. What can you say of acids, alkalies, salts? 

16. What is "washing soda?" How should it be 

used? When should it no/ be used? 

17. Why does strong soap or washing soda harm 

varnish or paint? 

18. What is the cause of tarnish on metals? How 

can it be removed and prevented ? 

19. What advantages has ammonia for use in the 

laundry ? 

20. Do you understand everything given in this les- 

son paper? Are there any questions you would 
like to have answered? 
Note. — After completing the test sign your full name. 



CHEMISTRY OF THE HOUSEHOLD. 

A Day's Chemistry. 
PART III. 



CHEMISTRY OF BAKING POWDER 

We will suppose that after the strenuous course of 
cooking, washing, and cleaning outlined for the morn- 
ing, that the housekeeper still has strength to make 
soda biscuits for tea, and we will study the chemical 
action involved. 

One of the first chemical methods of securing car- 
bon dioxide to use in making bread rise, was by putting 
hydrochloric acid and cooking soda together in a dough 
which might be put into the oven before the gas es- 
caped from it. 

Cooking soda is a salt called bi-carbonate of sodium. cooking 
It differs from the ordinary mono-carbonate of soda 
(washing soda) in yielding twice as much carbon diox- 
ide in proportion to the sodium part of the compound. 
The saleratus of our grandmother's time was bi-car- 
bonate of potash, made from wood ashes. The name 
is still used, but at all stores, cooking soda would be 
delivered invariably if saleratus were asked for. The 
true saleratus costs ten times as much as the soda and 
is no more effective. The carbonic acid is easily set 
free by chemical compounds of an acid nature, and 
new chemical compounds result. 



Soda 



90 



CHEMISTRY OF THE HOUSEHOLD. 



Heating 

Cooking 

Soda 



Early 
Experiments 



Experiment. Put a little cooking soda into any- 
acid — lemon juice, vinegar, almost any fruit juice — 
and the carbon dioxide will be seen to escape in tiny 
bubbles. Part of the acid unites with part of the soda, 
forming a new salt, and the acid taste will be much 
reduced or lost. 

Part of the carbon dioxide in sodium bi-carbonate 
is driven off by simply heating, leaving ordinary 
sodium mono-carbonate, washing soda. In using this 
process, cooking soda is mixed with the flour. The 
high temperature of the oven drives off carbon dioxide, 
and the bread puffs up. It is light, but yellow in 
color. The sodium carbonate remains in the bread 
and its alkaline nature serves to neutralize the acid 
fluids of the stomach (gastric juice) so that digestion 
of the bread may be retarded. The sodium carbonate 
also acts in some way upon the gluten producing an 
unpleasant odor. 

Among the first methods proposed was one undoubt- 
edly the best theoretically, but very difficult to put in 
practice. This depended upon the liberation of carbon 
dioxide from bi-carbonate of sodium by means of 
muriatic acid — the method already described. The 
liberation of gas is instantaneous on the contact of 
the acid with the ''soda" and even a skilled hand can- 
not mix the bread and place it m the oven without the 
loss of much of the gas. Tartaric acid, the acid phos- 
phates, sour milk (lactic acid), vinegar (acetic acid); 



BAKING POWDER. 



9t 



alum, all of which hav^ been used, are open to the 
same objection. 

Cream of tartar is the only acid substance commonly 
used which does not liberate the gas by simple con- 
tact in cold solution. It unites with "soda" only when 
heated, because it is so slightly soluble in cold water. 

Experiment. To illustrate this stir a little soda and 
"cream of tartar" into some cold water in a cup. Ip 
another cup mix the same amounts of each in warm 
water. Note the difference in the action produced. 

To obtain an even distribution of the gas by thorough 
mixing, cream of tartar would seem to be the best 
medium by which to add the acid, but because there are 
other products which remain behind in the bread in 
using ajl the so-called baking powders, the healthful- 
ness of these residues must be considered. 

Common salt is the safest residue and perhaps that 
from acid phosphate is next in order. 

The tartrate, lactate, and acetate of sodium are not 
known to be especially hurtful. As the important 
constituent of Seidlitz powders is Rochelle salt, the 
same compound as that resulting from the use of 
cream of tartar and ''soda," it is not likely to be very 
harmful, even in the case of the habitual "soda bis- 
cuit" eater, because of the small quantities taken. 

The various products formed by the chemical de- 
composition of the alum and "soda" are possibly the 
most injurious, as these are sulphates, and are thought 



Cream of 
Tartar 



Injurious 
Products 



/ 



92 CHEMISTRY OF THE HOUSEHOLD. 

I 

to be the least readily absorbed salts. 'The sale of 

"alum" baking powder is increasing, as it is cheaper. / 

Taking into consideration then the advantage given 
by the insolubility of cream of tartar in cold water, 
and the comparatively little danger from its derivative 
— Rochelle salt — it would seem to be, on the whole, the 
best substance to add to the soda in order to liberate 
the gas, but the proportions should be chemically ex- 
act, since too much alkali would hinder the process of 
digestion. Hence baking powders prepared by weight 
and carefully mixed, are a great improvement over 
cream of tartar and "soda" measured separately. As 
commonly used, the proportion of soda should be a 
little less than half. 

LIGHTING 

By the time supper is over or even before, during a 
large portion of the year daylight has gone. Our 
grandmothers would have brought out the candles. 
Perhaps we shall use a candle to light our way while 
we carry the butter and food into the cool cellar. 
The Candle The caudlc flame although small in area is typical of 

all flames. Flame indicates the burning of a gas for 
solid substances in burning simply glow and do not 
burn with flame. When wood and soft coal burn, 
gases are set free by heat and these gases burn over the 
bed of fuel, giving the flames. 

The o^eneral form of the candle flame is a cone 
widest above the base, or about at the top of the wick. 
If it is examined carefully it will be seen to consist 



Flame 



LIGHTING. 



93 



of three layers. Fig. 21. The interior part is dark, 
giving out no Ught. The second is yellow and is the 
luminous part, and surrounding this and most easily 
seen at the base, is a very thin blue layer. 

Experiment. If a small splint of v^ood or a match 
be placed across the lower part of the flame near the 
wick for a moment, it will be charred where the outer 
layers of the flame have touched it, but the centre will 
not be changed. Press a piece of card board quickly 
down on the flame from above 
and remove it before it is set on 
fire, and a ring of scorched paper 
will show the shape of the hot 
part of the flame. 

The candle consists of hydro- 
carbons (compounds of carbon 
and hydrogen). When a match is 
applied to the wick, the hydrocar- 
bons are melted and the liquid 
rises on the wick by capillary at- 
traction. The heat changes this to 
gas (or vapor) which is set on fire, 
since at the high temperature it easily unites with the 
oxygen of the air. There is plenty of oxygen present, 
but it is all seized upon by the carbon and hydrogen 
in the outer parts of the column of gas rising from the 
wick, so that none reaches the centre. The gas diffuses 
outward toward the oxygen continually, so that the 
inner cone may be regarded as a gas factory. The yel- 




Fig. 21. Flame of a 
Candle. 



94 



CHEMISTRY OF THE HOUSEHOLD. 



Nature 
of Smoke 



Explosions 



Explosive 
Mixtures 



low light is caused by the incandescence or glowing of 
small particles of carbon, heated to "white heat." 
These are set free from the compounds where the hame 
is very hot and they are not yet united with oxygen. 

Flames "smoke, '^ that is, throw off unburned car- 
bon when there is an insufficient supply of oxygen. 
Any device which constantly renews a steady supply of 
air (with oxygen) will make the flame burn better. 
The chimney of a lamp does this by protecting the 
flame from wind and by making, enclosing, and direct- 
ing upward a current of air. The chimney makes 
the lamp "draw," as the chimney of the house makes 
the stove "draw." 

When the air is mixed with an inflammable gas and 
the temperature of any part is raised to the kindling 
point of the gas, as happens if a light is brought into 
such a mixture, an explosion takes place. The flame 
spreads through the whole and combination ensues 
everywhere almost instantly. Great heat is produced 
and the gases expand suddenly and with violence. If 
the gases are confined, the enclosing walls may be 
broken by the pressure. Contraction follows this ex- 
pansion and air rushes in, producing a second sound. 
The sounds occur so near together as to give the im- 
pression of one. 

In a mixture of inflammable gas and air there must 
be a certain proportion of each to give conditions which 
will produce an explosion. A very small amount of 
gas in the air will not explode under any conditions, 



LIGHTING. 



95 



as when there is an odor of coal gas in the room from 
which no explosion follows even though a light be 
present. On the other hand, a mixture containing a 
large proportion of inflammable gas and a little air 
will not explode. The proportion of air to gas in an 
explosive mixture varies in different cases, but in gen- 
eral ranges from about twelve to five parts of air to one 




Fig. 22a. The Effect of Wire Gauze on a Gas Flame. 

part of gas'. It is, of course, never safe to rely on the 
chance of the correct proportions of gas and air not be- 
ing present. 

Explosions sometimes occur by unwise use of kero- 
sene in kindling a fire in a stove. If the kerosene is 
poured upon a fire already burning, enough vapor of 
kerosene may be produced to give a disastrous explo- 
sion. Soaking wood or paper in kerosene for use as 
kindlings and then lighting would produce no such 
dire results. 



96 



CHEMISTRY OF THE HOUSEHOLD. 



Safety 
Lamps 



Kerosene 
Lamps 



Explosions in mines are usually caused by a ga« 
called fire-damp and composed of carbon and hydrogen. 
When this escapes from the coal and becomes mixed 
with air, it is very explosive. If a miner brings a 
naked flame into the mine, the fire-damp will ignite 
and disaster results. A safety lamp was devised by 
Davy for use in such dangerous places. It was found 
that a gas is cooled below its kindling temperature in 
passing through a fine wire gauze. 
Lamps surrounded by such a gauze may 
be taken into a mine with comparative 
safety. Fig. 22. 

The action of the wire gauze upon the 
gas may be studied by holding over a 
gas jet a piece of fine wire netting, such 
as is used in window screens, and then 
lighting the gas above the netting. Fig. 
22a. It will be seen that the gas below 
the netting is very slow in igniting, 
since it does not readily become sufficiently heated, the 
wire netting cooling it below its kindling point. 

The kerosene lamp gives light by the principle 
already described. The reservoir of the lamp corre- 
sponds to the cup of melted tallow at the top of the 
candle. The oil is drawn to the top of the wick by 
capillary attraction, where the heat vaporizes it ; so 
that vapor and not oil is what really burns. The struc- 
ture of the flame is precisely like that of the candle, 
although its shape differs, because of the shape of the 
wick. 




Fig. 22 



LIGHTING. 



97 



Illuminating gas is today the source of light in most 
city houses. There are two kinds of gas now fur- 
nished for this purpose. Coal gas is obtained from 
the destructive distillation of soft coal. Receivers 
or retorts of iron or fire clay are filled with soft coal 
and heated to i ioo° or more. From these retorts tubes 
lead up into a large pipe called the hydraulic main, 



r\ 




Service Main 



FIG. 23. MANUFACTURING OF COAL GAS. 



through which water is kept flowmg. As the coal be- 
comes heated, a number of different substances are 
given of¥, which at this high temperature are in the 
gaseous state. Some of them dissolve in the water 
of the hydraulic main, but those needed for illuminat- 
ing gas are not soluble and passing out of the main, 
they travel through several hundred feet of vertical 
pipe called the condenser, where more water removes 
any impurities which may have escaped from the 
hydraulic main. 



Coal Gas 



98 



CHEMISTRY OF THE HOUSEHOLD. 



Purifying 
Coal Gas 



Aniline 



Water Gas 



The gases are then passed on through numerous 
other devices to remove remaining traces of impurities, 
and are finally collected in a circular chamber known 
as the gas-holder, from which they are distributed to 
the consumer. Fig. 23. 

If the purification is not perfect, the coal gas will 
contain sulphur compounds, and these on burning pro- 
duce oxide of sulphur, which is further changed by 
moisture and the air into sulphuric acid. The quan- 
tity produced may be very minute and yet in time 
may be sufficient to damage books and fabrics. 

The materials which collect in the hydraulic main 
and the condensers contain many useful substances, 
one of the most valuable being ammonia. Among the 
most interesting substances obtained from coal tar is 
aniline from which beautiful dyes are made. Aniline 
itself is a colorless liquid, but in combination with 
other chemical substances it yields a wide range of 
beautiful colors now used in dyeing. Other useful 
substances obtained from the distillation of coal tar 
are carbolic acid, a disinfectant, and naphthalene 
which is sold in the form of moth balls. 

In some cities what is known as water gas forms 
the basis of the illuminating gas. This is made by 
passing very hot steam over red hot anthracite cr»al 
or coke. The oxygen of the water unites with the 
carbon of the coal, forming carbon monoxide — a com- 
pound of one part oxygen and one part carbon — and 
the hydrogen of the water is set free. Both the gases 



LIGHTING. 



99 



thus formed will burn, but in burning they produce a 
colorless flame. It is therefore necessary to mix with 
them some gases containing much more carbon which 
will give light when burning. The mixture is stored 
and distributed like coal gas. 

This gas is cheaper to manufacture in most locali- 
ties, but it contains much more carbon monoxide which 
is a very poisonous gas. Much discussion has arisen 
as to the safety of using water gas and in some places 
its manufacture is forbidden by law. 

The destructive distillation of vegetable and animal 
life in the depths of the earth, caused by the great 
heat within the earth, has in some places given rise 
to petroleum and natural gas. The gas gave a cheap 
and convenient fuel, but unfortunately the supply is 
becoming rapidly exhausted. 

An illuminating gas of growing importance today 
is acetylene. This is a compound of carbon and hydro- 
gen and is prepared by the action of water upon cal- 
cium carbide, which is a compound of carbon and the 
element calcium. Calcium carbide is manufactured in 
large quantities at Niagara Falls where pure lime 
mixed with powdered charcoal is fused at an intense 
heat. A dark gray crystalline solid results which, 
when mixed with water, produces acetylene gas and 
slaked lime. 

Acetylene is a colorless gas of characteristic odor, 
soluble in water, and explosive if mixed with air. 
With an ordinary burner it makes a yellowish smoky 



Natural 
Gas 



Acetylene 



100 



CHEMISTRY OF THE HOUSEHOLD. 



Acetylene 
Generators 



flame, but with a properly constructed burner, it gives 
a brilliantly white light, very like sunlight. Colors 
appear at their true values seen in this light. The 
flame is an intensely hot one. In acetylene burners 
the gas escapes through two very minute holes directed 
obliquely towards each other, as shown in Fig. 24. 





FIG. 24. ACETYLENE GAS BURNERS. 

The gas has been somewhat in disrepute because of 
lack of a suitable arrangement for making and storing 
it. Many generators are upon the market, it is true, 
but very few of these are really safe. As soon as a 
reliable one is obtainable, the gas will be widely used 
for lighting. It may also be used for cooking, but at 
present is rather expensive. One form of generator 
is illustrated in Fig. 25. The calcium carbide in 
lumps is fed automatically into water as long as the 
gas is used. When the storage tank is nearly full the 
supply of carbide is automatically shut ofif. In an- 
other style, which is also automatic, water is fed on 
to the lumps of carbide. Both styles have their advo- 
cates, but the lump feed generator is most generally 
recommended. The apparatus costs from about $65.00 
for a 10 light plant to $300.00 for a 100 light plant. 



LIGHTING. 



lOI 



A cheaper gas than acetylene is gasoline gas, some- 
times called carburetted air gas because it is com- 
mon air impregnated with the vapors of gasoline. It 
burns with a rich, bright flame similar to coal gas and 




Fig. 25. Acetylene Gaa Generator and Storage Tank. 

is conducted through pipes and fixtures in the same 
manner. It may be used in an ordinary gas stove. 

The gas machine consists of a generator containing 
evaporating pans, an automatic air pump operated by 



Gasoline 
Gas 



102 



CHEMISTRY OP THE HOUSEHOLD. 



Oxide of 
Calcium 



a heavy weight or by a water motor, together with 
a regulator or mixer. The general arrangement is 
shown in Fig. 26, the generator being entirely outside 
the building in which the gas is used. All such ma- 
chines require intelligent care, for several disastrous 




FIG. 2G. OASOLINI^ CAS PLANT. 

explosions have taken place when such care has not 
been given to the apparatus. 

LIME. 

One of the common chemical substances found about 
the country house at least is quick lime, used for 
whitewash and as a deodorizer. 

The term lime usually means the oxide of the element 
calcium. Its commonest compound is calcium carbon- 
ate which is found in nature as limestone, chalk, mar- 
ble, coral, shells, and several other familiar substances. 
Calcium is also found combined with sulphur and 



Quick 
Lime 



LIME. 103 

oxygen in the compound calcium sulphate, which is 
the mineral gypsum from which plaster of Paris is 
made. Bones contain a considerable amount of cal- 
cium phosphate and egg shells, calcium carbonate. 

Lime, the oxide of calcium, is made by heating 
broken pieces of limestone in furnaces called lime kilns. 
The calcium carbonate as a compound is broken up, 
carbon dioxide gas being given off and calcium oxide 
left. This freshly formed oxide is called "quick lime," 
and when it is exposed to moist air, it attracts water 
and changes to a form called chemically, calcium 
hydroxide and, commonly, "slaked lime." Quick lime 
may be used to dry the air of damp cellars, etc., because 
of this property. The process of slaking the lime is 
also accomplished by treating quick lime with water. 
When this is done, much heat is evolved and the hard 
lumps crumble to a soft powder and increase consider- 
ably in bulk. The rise in temperature shows that 
chemical change is taking ]:)lace. 

Slaked lime will dissolve slightly in water, yield- 
ing lime-water. This is a mild alkali and has several ^**®'" 
household uses. It may be prepared by pouring two 
quarts of boiling water over about a cubic inch of 
unslaked lime. Stir it thoroughly and let it stand over 
night ; in the morning pour off the liquid and treat 
the sediment with hot water a s(^cond time. When the 
sediment has again settled, pour off the clear liquid 
and bottle this. It is mixed with milk and fed to 
young children and invalids to prevent acidity of the 



Lime 



104 



CHEMISTRY OF THE HOUSEHOLD. 



Mortar 

and 

Plaster 



Hydraulic 
Cement 



stomach and make the milk more easily digested. 
Lime-water and oil form one of the best remedies for 
burns. The alkali of the lime neutralizes the acid 
nature of the burn. 

Mortar is made of slaked lime and sand. When 
this is spread upon the walls, the lime slowly absorbs 
carbon dioxide, always present in the air, and changes 
to carbonate of lime. The water is given off into the 
air (evaporates) and the mass becomes hard. Of 
course the surface becomes carbonate sooner than the 
deeper parts because this has closer contact with the 
air, and it therefore takes considerable time for all the 
plaster to harden. The water contained in the mortar 
soon dries, but while the mortar is becoming hard, 
more water is continually formed in the chemical pro- 
cess, so that it requires a long time for the new plaster 
to become quite dry. It is considered unhealthy to 
live in rooms with newly plastered walls. This may 
be because such walls are damp, thus producing damp 
air, or it may be because the moisture in the walls 
interferes with the passage of air and other gases 
through the walls — a process little considered as a 
rule, but of great importance. 

Certain varieties of limestone contain other salts, 
such as magnesium carbonate. Lime made from these 
does not soften from exposure to the air. It will, 
however, harden after long contact with water, and 
such substances are known as cements. Portland cement 
will harden under water. 



LIME. 



lOS 



Quick-lime is a strong alkali and does the work of 
such substances. It is used in tanneries in taking 
hair from hides and also in decomposing fats for mak- 
ing candles. When dead animal substance is buried 
in lime, the process of decomposition is greatly hast- 
ened, probably because the lime unites with all water 
present while the strong alkali acts upon the fats re- 
ducing them to soaps of different kinds. 

Whitewash is simple slaked lime mixed with water. 
It is very cleansing in its effects and also gives the ap- 
pearance of freshness and cleanness. When newly ap- 
plied, it is nearly colorless, for the calcium hydrate is 
colorless ; this in the air soon changes to calcium car- 
bonate which is white and opaque. 

CHEMISTRY AND ELECTRICITY. 

In most houses electricity is used for operating the 
door bell, table bell and perhaps the electric gas light- 
ers. Wei have learned how stored up chemical energy 
is changed into heat and force in the stove and in the 
human body ; but in the electric cell, chemical energy 
is changed into electrical energy. 

If a strip of pure zinc be placed in a weak solution 
of acid, no chemical action takes place. Place in the 
same solution a strip of sheet copper and again no 
action takes place ; but let the copper and the zinc be 
brought in contact, or connected by a copper wire, and 
immediately vigorous chemical action will begin at the 
surface of the copper plate ; bubbles of hydrogen col- 
lecting there. This action is as follows : the zinc dis- 



Whitewash 



A Voltaic 
Cell 



io6 



CHEMISTRY OF THE HOUSEHOLD. 



solves in the acid and hydrogen is set free. This 
hydrogen travels with an electric current set up in the 
liquid, passing from particle to particle through the 
liquid until it reaches the copper. Here the hydrogen 
stops, but the electric current passes up the copper 
plate and over the wire to the zinc and down that ^o 



Leclanche 
Cell 





Fig. 27. A Simph' 
Voltaic Cell. 



Fig. 



28. A Leclanche 
Cell. 



the liquid and so on. This arrangement of acid and 
metals is called a simple voltaic cell. Fig. 27. 

Other cells are arranged with different liquids and 
solids to gain various ends, and several cells may be 
united by wires between the plates to gain additional 
strength of current. The form of cell often employed 
to work electric bells is the Leclanche cell. Fig. 28. 
This consists of a plate of carbon (or a porous cell 
containing carbon), in place of the copper, a strip 
or rod of zinc, and a solution of ammonium chloride 



ELECTRICITY. 



107 



which takes the place of the acid. The zinc is not 
affected by the ammonium chloride unless it is con- 
nected with the carbon, but when there is a circuit 
for the electricity, a current is generated. The com- 
mon conductors of the electric current are the metals 
and carbons. 




Fig. 29. A Battery of Cells Connected iu Series. 

The zinc is gradually changed to zinc chloride, at 
the expense of the ammonium chloride, and after a 
time bpth the zinc and the ammonium chloride must 
be renewed. In renewing the battery, the jars should be 
cleaned out carefully and the zincs renewed if they 
are completely eaten through. A quarter of a pound 
of pure ammonium chloride (sal-ammoniac) is dis- 
solved in enough water to about half fill a jar. When 
the carbon and the zinc are replaced, this will bring 
the liquid up to two inches from the top. The jar 
should not be filled too full. The wires which have 
been disconnected should be reconnected as before. 

For bell work the cells are usually connected up "in 
series," that is, the zinc of one cell is connected to 



Renewing: 
Batteriea 



Oelli i& 
Series 



lo8 



CHEMISTRY OF THE HOUSEHOLD. 



Plant Foods 




the carbon of the next, the outside circuit being estab- 
lished between the end carbon and end zinc. Fig. 29. 
If there is a short circuit anywhere 
in the Hne, that is, if the current has a 
chance in any way to flow from one 
wire to the other without going 
through the bell or other apparatus, 
the batteries are very quickly ex- 
hausted. 

A modification of this cell has been 
made in which the spaces inside it are 
filled with some spongy mass in the 
pores of which the ammonium chlor- 
ide is held. These may easily be car- 
ried about without danger of spilling solutions. They 
are called dry cells and when exhausted cannot read- 
ily be renewed. 

PLANTS. 

Most housekeepers have at least a few house plants 
and many have gardens which occupy part of the time 
each day. All foods are directly or indirectly produced 
by plants and it is well to consider also what food these 
living things require in their turn. 

Plants are able to take from the materials forming 
the crust of the earth and from the air surrounding 
them all that they need for their life. The leaves of 
the plants, because of the green substance called 



Fig. 30. A Dry Cell. 



PLANTS. 



109 



Upper Surface 

ooocdcdcd 




Bvea.tKin<j Pones 



Fig. 31. Section Through 
a Leaf. 



chlorophyl, have the power of decomposing carbon 
dioxide gas in a such a way that plants make use of 
the carbon and breathe out oxygen. Fig. 31. This 
separation is very difficult to 
make in the laboratory. The en- 
ergy of sunlight is utilized by the 
plant for this work, for the action 
does not take place in darkness. 
In this way plants return to the 
air the oxygen so necessary for 
animal life and are themselves 
fed in part by the useless and 
even harmful gas exhaled by ani- 
mals. 

The soil on which the plant grows furnishes the 
mineral matter needed. When plant tissues are 
burned, these mineral substances remain as ashes. 
When the ashes of plants are analyzed, they are found 
to consist of potash, soda, iron, and lime in the form 
of phosphates, sulphates, and silicates. Some of these 
substances are present in the soil in inexhaustible 
quantities, but others are less abundant and unless the 
soil be fertilized from time to time, the plant soon 
uses them up. These less abundant substances are 
phosphates-, potash, and nitrogen. 

The lover of house plants has long resorted to 
various expedients for feeding them, and many plant 
foods are now sold and in common use. In using these 
for manuring potted plants, care must be taken not to 



Chlorophyl 



Fertilizer, 



no CHEMISTRY OF THE HOUSEHOLD. 

' use too much, since strong solutions of them are likely 
to corrode the roots and kill the plants. 

Nitrogen and Although uitrogcu is a very abundant element, form- 
piant Life jj^g ^g j^^g been said, four-fifths of the air, yet it is com- 
paratively rare in forms which are of use to plants. 
As a rule plants cannot take it from the air and there- 
fore require soluble compounds of nitrogen for food. 
One of the most important of these is ammonia. This 
is formed when organic substances decay, its odor 
being very noticeable about stables. Its action with 
acids was described in the pages about cleaning and it 
was explained how it unites with acids to form salts, 
usually soluble. Sulphate of ammonia is the form used 
in agriculture. A very little ammonia in the water 
used on house plants is a good thing for them. 

It has been seen that plants by aid of sunlight breathe 
in carbon dioxide and breathe out oxygen gas. In 
addition to this, they also breathe as animals do, to a 
slight extent, taking in oxygen and breathing out car- 
bon dioxide. This action is more pronounced in dark- 
ness. 

Conservation '^^c woudcrful principle Called conservation is il- 

lustrated by what we know of plant life. Plants in 
growing store up energy derived from the heat and 
light of the sun. When they decay, or are burned, or 
are eaten by animals, exactly the same amount of 
energy is set free and changed into a new form, and 
just as much carbon dioxide as the plant breathed in, 
is given back to the air. A plant which was many 



PLANTS. Ill 

years in growing may be consumed in an hour or may 
decay slowly for years. In either case the same total 
amount of energy is set free, fast or slowly. This 
energy is most apparent as heat. In the growth and 
destruction of the plant both energy and matter have 
been transformed, but neither energy nor matter has 
been made or lost — it has merely taken on a new appear- 
ance. When animals feed on plants they transform the 
energy of sunlight which is stored up in the plant into 
energy of vitality. In this sense man and all animals 
are "children of the sun." 

CHEMICAL TERMS. 

To explain various chemical and physical phenomena 
the scientists consider that matter consists of certain 
small molecules and atoms. 

If a drop of water be divided and sub-divided in- 
definitely, it is conceivable that a point would come 
w^ien it; could not be divided further by physical means. 
This final bit of water is called a molecule. It would 
be far from visible by the most powerful microscope. 
From calculation which we will not go into, we learn 
that a few hundred million ordinary sized molecules 
would cover the space of a pin head. 

If the water is broken up by some powerful force 
as by the electric current, we have seen that two dif- 
ferent substances are obtained — oxygen and hydrogen. 
Consequently the molecules of water must have been 
made up of other still smaller particles and these are 
called atoms. The atoms of a chemical element, then. 



Molecules 



112 



CHEMISTRY OF THE HOUSEHOLD. 



are of the same kind, for from an elemental substance 
like oxygen, only oxygen can be obtained by any 
means now known. 
Atoms The atoms may be likened to the letters of our alpha- 

bet and the molecules to the words. From a few dif- 
ferent kinds of atoms (letters) can be made a great 
variety of molecules (words). 

TABLE OF COMMON ELEMENTS. 



Aluminum 


Al 


Iodine 


I 


Oxygen 


O 


Arsenic 


As 


Iron 


Fe 


Phosphorus 


P 


Barium 


Ba 


(Ferrum) 




Silicon 


Si 


Boron 


B 


Lead 


Pb 


Silver 


Ag 


Calcium 


Ca 


(Plumbum) 




(Argentum) 




Carbon 


C 


Magnesium 


Mg 


Sodium 


Na ' 


Chlorine 


CI 


Manganese 


Mu 


(Natrium) 




Copper 


Cu 


Mercury 


Hg 


Sulphur 


S 


Gold 


Au 


(Hydrargyrum) 


Tin 


Sn 


(Aurum) 




Nickel 


Ni 


(Stannum) 




Hydrogen 


H 


Nitrogen 


N 


Zinc 


Zn 



Chemical 
Si^ns 



The atoms of an element are all exactly alike. They 
weigh the same and act the same whatever their 
source. Two or more atoms of an element may com- 
bine to make a molecule of that element. The mole- 
cules of a chemical substance are always composed of 
the same number and kind of atoms. 

To express the composition of substances chemists 
have made use of certain abbreviations and signs. To 
indicate an atom of hydrogen the letter H is used and 
for oxygen, the letter O, for nitrogen, N, and so on as 
shown in the table. 

When expressing a compound the number of atoms 
is indicated by sub-script; for example, H^ means two 



CHEMICAL TERMS. 



"3 



atoms of hydrogen; H2O expresses two atoms of 
hydrogen and one atom of oxygen, and as we have 
found, this is the composition of water ; so HgO is the 
chemist's short way of indicating water. These are 
called chemical formulas. The formula for sulphuric 
acid is H2SO4. This indicates that it is made up of two 
atoms of hydrogen, one atom of sulphur, and four 
atoms of oxygen. The following table gives the chemi- 
cal formulas of many of the chemical substances found 
in the household. 

THE HOUSEKEEPER'S LABORATORY. 

All modern science is based upon experiment. 
Chemistry was hardly a science until experimental re- 
search began. It must be confessed that the average 
housewife seldom thinks of making experiments. She 
is apt to remain helpless before any new problem of 
the home without printed directions or advice from 
friends. Very often the easiest and surest way to find 
out a tiling is to try it. Use your kitchen as a labora- 
tory. It would, of course, be most unwise to make ex- 
periments on expensive materials. For example, if 
a stain was to be removed from colored goods, it would 
be best to find the effect of the chemicals to be used on 
some small piece of the fabric. 

To test the color of a sample of gingham for fastness 
in washing, try a part of the sample in soap and hot 
water and see if the color ''runs" or stains the water. 
Dry and iron the piece treated and compare with the 
portion of the original sample kept. A sample can be 



Expressing 
Molecules 



Experiments 



Testing 
Colors 



114 CHEMISTRY OF THE HOUSEHOLD. 



TABLE OF COMMON SUBSTANCES AND THEIR FORMULAS. 



SUBSTANCE 


FORMULA 


SUBSTANCE 


FORMULA 


Water 


H2O 


Calcium Oxide 




Peroxide of Hydro- 




(Lime) 


CaO 


gen 


HzO, 


Lime Water . . . . 


CaOH 


Sulphuric Acid . . 


H2SO4 


Calcium Carbonate 


CaCOa 


Sulphur Dioxide . 


SO2 


Calcium Hypo- 




Hydrochloric Acid 


HCI 


chlorite (Chloride 
of Lime) .... 


Ca(C10)a 


Acetic Acid .... 


C2H4O3 


Sodium Thiosul- 




Tartaric Acid . . . 


CiHsOe 


phite ("Hypo") . 


NaQSjOa 


Jream of Tartar 




Cane Sugar .... 


CisHaaOii 


(Acid potassium 
tartrate) .... 


KC4H5O6 


Milk Sugar .... 


Cl2H220ll + H20 


Carbon Dioxide . . 


CO2 


Grape Sugar . . . 


C«Hl209 


Carbon Monoxide . 


CO 


Starch 


(C6HioO«)x 


Caustic Soda . . . 


NaOH 


Cellulose 


(C8Hio05)y 


Caustic Potash . . 


KOH 


Stearine (in fat) . 


C3H6(02CihH3s)3 


Sodium Carbonate 




Palmitin (in fat) . 


C3H6(02Cl6H3l)3 


{Anhydrous) . . 


NaoCOa 


Soap -' 


Na02Ci8H35, 
NaOsCisHai. 


Sodium Carbonate 






etc. 


( Crystalline) 
(Washing Soda) . 


NaoCOs+lSH.O 


Albumen ...... 


{Not dejim'tely 
known.) 


Sodium Bicarbon- 




Alcohol 


CaHsOH 


ate 


NaHCOa 


Wood Alcohol . . 


CH3OH 


Ammonia {gas) . . 


NH, 


Glycerine 


C3Hb(OH)3 


Ammonium Hy- 
drate (Aiiinionia 




G'soline, N'phtha \ 


C6H14, C7H1 s. 


Water) 


NH40H 


Benzine, etc. „ . \ 


CsHiH. etc. 



THE HOUSEKEEPER'S LABORATORY 



115 



tested for fastness to light by exposing to direct sun- 
light for a day or two, saving a portion of the cloth as 
before for comparison. If the dye will stand direct 
sunlight without appreciable change for this length of 
time, it will not give much trouble by fading. Wall 
paper may be tested for fading in a similar way. 

The industrial chemist always endeavors to test 
materials in a manner as nearly like the way they are 
to be used as possible. For example, if he were testing 
two samples of flour to be used for making bread, he 
might make up two small loaves, using carefully 
weighed quantities of each sample of flour and other 
materials and baking the loaves at one time, compare 
the result. In such cases it is usual to have a ''stand- 
ard" flour or other material to use for comparison. 

This method of testing by comparison could often 
be used by housekeepers provided reasonable care 
were taken as to weights and conditions. Working 
thus, flour, baking powder, soap, spices, flavoring ex- 
tracts, in fact almost all the raw materials of the kitchen 
and laundry could be tested. 

The chemicals for househald use are chiefly acids, 
alkalies, and solvents for grease. Acids and alkalies 
are opposed to each other in their properties and if too 
much of either has been used, it may be rendered in- 
nocent or neutralized by the other ; as when soda has 
turned black silk brown, acetic acid or vinegar will 
bring the color back. 



Testing by 
Comparison 



Household 
Chemicals 



ii6 CHEMISTRY OF THE HOUSEHOLD. 

Acids for the The acicls which should be on the chemical shelf 

a ora ory £^^ ^^^ houschold are acetic, hydrochloric (muriatic), 
oxalic. Vinegar may be used in many cases instead of 
acetic acid, but vinegar contains coloring matter which 
stains delicate fabrics and it is better to use the puri- 
fied acid. Hydrochloric and oxalic acids are strong 
acids and will harm most household materials if al- 
lowed to act for long time. Acetic acid is a weak acid 
and as it is volatile, evaporates without becoming con- 
centrated as do the others. 

Some bright blue flannels and other fabrics, when 
washed with soap or ammonia become changed or 
faded in color. If acetic acid or vinegar be added to 
the last rinsing water, the original appearance may be 
restored. Not all shades of blue are made by the same 
compounds, hence not all faded blues can be thus re- 
stored. 
Care of The usc of tlicsc acids has been indicated in the 

Chemicals . , , . - . , , 

previous pages, and there remams to be considered, 
only certain cautions. Hydrochloric acid is somewhat 
volatile. It will escape even around a glass stopper 
and will eat a cork stopper ; therefore, either the glass 
stopper should be tied in with an impervious cover — 
rubber or parchment — or a rubber stopper used, for the 
escaping fumes will rust metals and eat fabrics. 

Oxalic acid should be labeled POISON. 

The bleaching agents, ''chloride of lime" and Javclle 
water owe their beneficent effect to substances of an 
acid nature which are liberated from them. They 



THE HOUSEKEEPER'S LABORATORY. 117 

should all be used in solution only, and should be kept 
in bottles with rubber stoppers. 

Sulphurous acid gas, obtained by burning sulphur, 
will often remove spots which nothing else will touch. 
The amount given off from a burning sulphur matcli 
will often be sufficient to remove from the finger fruit 
stains or those made by black kid gloves. 

The alkalies which are indispensable are: • Aikaiiet 

1st. Ammonia — better that of the druggist than the 
often impure and always weak ''household ammonia." 
The strong ammonia is best diluted about one-half, 
since it is very volatile, and much escapes into the air. 

2nd. Potash and Caustic Soda, which are to be had at 
the grocers in small cans. The lye obtained from wood 
ashes owes its caustic and soap-making properties to 
potash. The caustics are corrosive in their action, and 
must be used with discretion. 

Crystallized sodium carbonate, the sal-soda of the 
grocer, is chemically speaking a salt and not an alkali, 
but it gives all the effect of one, since the carbonic acid 
is so weak that it readily gives place to other sub- 
stances. 

Sal-soda is a very cheap chemical, since it is readily 
manufactured in large quantities, and forms the basis 
of most of the washing powders on the market. With 
grease, it forms a soap which is dissolved and carried 
away. 

3rd. Borax is a compound of sodium with boric acid, 
and acts as a mild alkali. It is the safest of all the 



ii8 



CIJRMISTRY OP THE HOUSEHOLD. 



Solvents 



Closet for 
Chemicals 



alkalies, and affects colored fabrics less than does 
ammonia. 

Solvents for grease are alcohol, chloroform, ether, 
benzine, naphtha, gasolene — all volatile — kerosene and 
turpentine. Of these chloroform is the most costly, 
and is used chiefly for taking spots from delicate silks. 
Fabrics and colors not injured by water may be treated 
by alcohol or ether. Benzine, naphtha or gasolene are 
often sold, each under the name of the other. If care 
is taken to prevent the spreading of the ring, they can 
be safely used on any fabric. They do not mix with 
water, and are very inflammable. 

The less volatile solvents are kerosene and turpen- 
tine. Kerosene is a valuable agent in the household, 
and since some of the dealers have ])rovided a deodor- 
ized quality, it should hud an even wider use. The 
lighter variety is better than the JSO-degrec fire test, 
which is the safe oil for lamps. As has been indicated 
in the preceding pages, the housewife will find many 
uses for this common substance. 

On account of the purity and cheapness of kerosene, 
turpentine is less used than formerly, although it has 
its advantages. 

These household chemicals should have their own 
closet or chest, as separate from other bottles as is the 
medicine chest, and es])ecially should thev be separated 
from it. Many distressing accidents have occurred 
from swallowing ammonia by mistake. 

Tn addition to these substances, certain others may be 
kept on hand, if the housewife has sufficient chemical 



THE HOUSEKEEPER'S LABORATORY. 



119 



knowledge to enable her to detect adulteration in the 
groceries and other materials which she buys. 

A few of these simple tests are given with the 
chemicals needed. 

Directions for Using the Housekeeper's Laboratory. 
When directed to make a solution acid or alkaline, 
always test it by means of the litmus paper : 

Blue turned to red means acid. Red turned to blue 
means alkaline. 

Only by following the directions can the test be 
relied upon. Under other circumstances than those 
given, the results may mean something else. 

Use the acids in glass or china vessels only. Metals 
may be attacked. Do not touch brass with ammonia 
or marble with acid. Aluminum is quickly corroded by 
the alkalies. 

Heating or burning a substance often gives evidence 
of its character. Organic solids will char, leaving 
charcoaU (carbon) when heated and will disappear 
completely when burned. Some salts melt ; others do 
not. 

All the carbonates that the housewife is likely to 
meet will give an effervescence of carbon dioxide with 
muriatic acid and most of them with acetic acid. 

Substances of an acid nature will effervesce with a 
solution of cooking soda. The test will be more deli- 
cate if the solutions are warm. 

To test for sulphuric acid or soluble sulphate in soda, 
cream of tartar, baking powder, vinegar, sugar or 



Tests 



Vessels 



Carbonates 



120 



CHEMISTRY OF THE HOUSEHOLD. 



Lime Test 



Phosphates 



Chlorides 



Ammonia 



Alum 



syrup: Add muriatic acid to the solution (if the in- 
soluble part is sulphate of lime, it will dissolve in the 
acid on heating), then add barium chloride. A heavy 
white precipitate proves the presence of sulphuric acid, 
either free or combined. If the solution is not distinct- 
ly acid at first, it is not free. 

To test for lime in cream of tartar, baking powder, 
sugar or syrup : Make the solution alkaline with am- 
monia and ammonium oxalate. A fine white precipi- 
tate proves the presence of lime. Good cream of tartar 
will dissolve in boiling water, and will show only 
slight cloudiness when the test for lime is applied. 

To test for phosphates in cream of tartar or baking 
powder : Make acid by nitric acid, and add ammonium 
molybdate. A fine yellow precipitate or yellow color 
proves the presence of phosphates. 

To test for chlorides in soda, baking powder, sugar, 
syrup or water: Make the solution (a fresh portion) 
acid with nitric acid, and add silver nitrate. A white 
curdy precipitate or a cloudiness indicates chlorides. 

To test for ammonia in baking powder : Add a 
small lump of caustic soda to a strong water solution. 
Red litmus will turn blue in the steam, on heating. 

To test for ahtm in cream of tartar, baking powder 
or bread : Prepare a fresh decoction of logwood ; add 
a few drops of this to the solution or substance, ai?.^ 
render acid by means of acetic acid. A yellow color 
in the acid solution proves absence of alum. A bluish 



TESTS. 121 

or purplish red, more or less decided, means more or 
less alum. 

To test for starch in any mixture which has been starch 
cooked, simply moisten with dilute tincture of iodine 
such as is kept by the druggists. An intense blue color 
will show the presence of even a minute quantity of 
starch. If the substance has not been heated, boil a 
portion and let cool and then test with a few drops of 
iodine solution. Heat destroys the blue color of iodine 
with starch and therefore the test must be made in cold 
solutions. 

If the label of a washing powder claims it to be washing 
something new, and requires that it be used without 
soda, as soda injures clothes, it can be tested as fol- 
lows : Put half a teaspoonful of the powder into a 
tumbler, add a little water, then a few drops of muriatic 
acid. A brisk effervescence will prove it to be a car- 
bonate, and if the edge of the tumbler is held near the 
colorless flame of an alcohol lamp, the characteristic 
yellow color of sodium will appear and complete the 
proof. If the acid is added drop by drop, until no more 
effervescence occurs, and there remains a greasy scum 
on the surface of the liquid in the tumbler, the com- 
pound contains soap as well as sal-soda, for the acid 
unites with the alkali of the soap and sets free the 
grease. Acetic acid or a solution of oxalic acid may 
be used in place of the muriatic acid. 

If some very costly silver polishing powder is offered suyer 
as superior to all other powders, a drop or two of 



122 CHEMISTRY OF THE HOUSEHOLU. 

muriatic acid or of warm vinegar will decide whether 
or not it is chalk or whiting by the effervescence or 
liberation of the carbonic acid gas. 
^*Ss ^^ making all the foregoing tests, it is well to ob- 

serve the effect of the chemicals used on the substance 
to be tested for, and so become familiar with the char- 
acteristic color or appearance of the test. For example, 
before testing a washing powder, add a little acid to a 
soap solution and observe the greasy film produced, 
and in testing for alum add a very little alum solution 
to some flour and test with the logwood solution, not- 
ing the color given. This procedure will lead to more 
reliable results. 

Caution! Use a new solution of a fresh portion of 
the first one for each new test and follow directions ex- 
actly. This is essential to remember. 



CHEMISTRY OF THE HOUSEHOLD. 

PART III. 



Read Carefully. Place your name and address on the first 
sheet of the test. Use a light grade of paper and write on one 
side of the sheet only. Do not copy answers from the lesson 
paper. Use your own words, z'^ that your instructor may know 
that you understand the subject. Reau liio 'esson paper a num- 
ber of times before attempting to answer the questl'^Tis. 



1. What properties of "cream of tartar" make i 

suitable for baking powder? 

2. Explain how a candle is a gas factory. 

3. What conditions must be present for an explosion 

^o take place? 

4. What is "cooking soda ?" How does it differ from 

washing soda ? 

5. What is the principle of the Davy safety lamp? 

6. Describe the manufacture of coal gas. 

7. How is water gas made? What objectionable 

features has it? 

8. What is "quick lime" and what are its uses? 

9. How is electricity produced in a voltaic cell ? 

10. What does the chemical formula H0SO4 indicate? 



CHEMISTRY OF THE HOUSEHOLD. 

IT. How is ''conservation" illustrated in the life and 
decay of a tree? 

12. What can you say about the advisability of the 

housekeeper making experiments? 

13. How would you test for a carbonate? How for 

an acid without using litmus paper? 

14. How are tests made by comparison? 

15. Are there any questions you would like to ask re- 

lating to "A Day's Chemistry"? 

16. Have you any personal experience, original 

method, or new fact to ofifer, relating to the sub- 
jects taken up in the lesson on the ''Qiemistry 
of the Household" that would be of interest to 
your fellow students? 
Note.— After completing- the test, sign your full name. 



SUPPLEMENT 
CHEMISTRY OF THE HOUSEHOLD 

By Margaret E. Dodd, S. B. 

In reading many hundreds of test papers written 
by our students I have found that additional com- 
ments suggest themselves frequently, and it may be 
of interest to bring them together here. 

IMPURITIES IN WATER 

By the term impurities, we mean substances out of 
place. Pure water is oxide of hydrogen, H^O. If 
water has salt dissolved in it, for instance, the salt is 
an impurity for the water, though we do not think 
of salt as being an impure substance in itself. The 
mineral impurities in drinking water are seldom a 
source of danger, although if the amount is large, 
such water may not "agree" with persons not used 
to it. ' Mineral impurities will usually make the water 
hard, and therefore troublesome for laundry work 
and to some extent in cooking. 

LAUNDRY WORK 

Satisfactory water for laundry work must not only 
be clear and soft but it must be free from iron, from 
the discoloration due to decaying vegetable matter, 
clayey soil, and so on. It should also be free from any 
odor when hot. Muddy water may be cleared more 

127 



128 CHEMISTRY OF THE HOUSEHOLD 

or less satisfactorily by filtering it through sand or 
"by precipitation." In the latter method, dissolve 
a scant tablespoonful each of alum and borax in a 
little hot water, and add this amount to each gallon 
of water used, stirring it in, and allowing it to settle. 
The alum and borax react to form a cloudy substance 
which settles to the bottom, carrying the mud with it. 
The clear water must then be carefully poured or 
dipped off from the sediment. A siphon is an excel- 
lent contrivance for such a use. If a piece of garden 
hose is used, tie on a piece of wood so that it extends 
one or two inches beyond the end, to keep it above 
the sediment. Weight it with a piece of lead. 

When water made hard by carbonate of lime is to 
be softened, addition of any of the alkalis will soften 
it, for this reason. These carbonates will not dis- 
solve in water unless it contains carbon dioxide gas 
in solution. The alkalis added, unite with the gas, 
and the lime is thereby made insoluble and separated 
from the water. We do not see it as a rule, for there 
is in reality, very little of it, and this little separates 
in very tiny particles. Water which is hard in the 
clothes boiler frequently causes trouble because of 
tiny -bits of lime which separate from it and make 
spots upon the clothes. 

A spring situated in sandstone rock generally 
yields soft water because the sandstone is so slightly 
soluble, but one situated in limestone rock always 
gives hard water. Limestone is a very common rock, 



LAUNDRY WORK 129 

so many springs are of hard water. A shallow well 
is more apt to yield soft water than a deep one is, and 
a river has clearer and softer water near its source, 
where it runs over rocks, and through uncultivated 
land. 

Occasionally where free alkali is added to hard 
water, it unites with greasy or oily matter in the gar- 
ments being washed, and forms dark spots of soap 
insoluble in water. This is prevented to some extent 
by addition of a very little turpentine, and boiling 
such spotted garments in clean suds may dissolve out 
the stains if they have formed. This happens so sel- 
dom that the use of soda in laundry work (with cau- 
tion) for softening water is still to be recommended 

Washing powders are usually composed for the 
most part of washing soda, and as they cost more than 
soda, it is rather better to buy the latter. Moreover, 
the strength of the alkali may be more accuratelv 
judged. 

Water varies greatly in hardness, so it is difficult to 
give exact rules for softening it, though I am often 
asked for them. In general, for moderately hard 
water use: 

I level tablespoonful of sal soda to i gallon 

water. 
^2 level tablespoonful of powdered lye to i 

gallon water. 
I level tablespoonful of borax to i gallon 
water. 



130 CHEMISTRY OF THE HOUSEHOLD 

Do not use ammonia with very hot water, for heat 
liberates the ammonia gas, which is thus lost. 

Some students have thus described the use of ashes 
from hard wood: 

Add a quart or more of water to a quart of ashes. 
Boil it a few minutes, adding more water if necessary. 
Then add sufficient water to make a gallon. Let it 
settle, then pour off the water and strain it. Put 
enough of it in the wash water to secure a good suds 
with soap. The water dissolves the potash (potas- 
sium carbonate) from the ashes. So this is an eco- 
nomical method of getting this alkali. 

I have had many interesting letters on the subject 
of laundry work. Some of the processes described 
may be new to many of our students. 

One writer describes a method of using paraffine 
in washing. She dissolves a bar of soap in boiling 
water and adds to it a piece of paraffine almost as 
large as a walnut. She uses this in making a suds 
with boiling water in which the clothes are thoroughly 
boiled for twenty minutes or more, punching them 
ocassionally. They must be rinsed in several hot 
waters to ensure the removal of the paraffine, but 
she claims the clothes will be beautifully white. 

A number have advocated the use of kerosene in 
laundry work, especially with very much soiled articles. 
Both this and paraffine certainly act upon the oily 
film which entangles the dirt and thus make the wash- 
ing easier. The objection to their use is that more 



BLUING 131 

soap and more hot water and therefore more 
fuel must be used. Two tablespoonfuls of kerosene 
in a boiler of soapy water is about the right quantity. 
In this connection it should be said that when clothes 
are taken from the boiler, they should be put into 
tepid water, and pushed well into it, for lying in the 
air seems to set the dirt, probably because the- fibres 
contract as they cool, so that foreign particles are 
enclosed in the cloth and cannot fall out into the rinse 
water. 

Kerosene is excellent to use in washing dish towels. 
Make a strong soap suds, putting in a tablespoonful 
of oil to a gallon of water. Soap the towels well, and 
boil them in this suds for half an hour or so. Then 
wash, rinse and dr}' them, in the fresh air. Kerosene 
is somewhat volatile, and its odor will escape in. time. 
When kerosene has been used, the wringer, tubs, etc., 
will need very careful cleaning to remove any film of 
oil before it has time to catch dust. 

-' BLUING 

There are three kinds of bluing now on the market. 
The action and disadvantages of Prussian Blue have 
been described. It gives a better color, however, 
than either of the other two . A second kind is Ultra- 
marine blue. This, also, is an iron compound, but 
it does not decompose with alkali. It is what we 
often buy as the "ball bluing," and is insoluble in 
water. Water, however, causes it to break up into very 



132 CHEMISTRY OF THE HOUSEHOLD 

minute particles which spread through the Hquid and 
give it a blue color. The water must be kept stirred, 
and one must be careful in using it that the clothes 
do not get streaked. The balls of bluing should be 
tied up in a cloth and washed from this into the water. 
It is well to prepare it in a separate dish and then add 
it to the water. Indigo blue is easier to use, but does 
not give so good a color. Preparations of indigo 
for laundry work may still be obtained. 

Here is a method of cleansing knitted worsted goods 
which was strongly recommended. Wash the gar- 
ment in gasoline, and allow it to dry. Then shake it 
well in a tight box with flour or fuller's earth, allow- 
ing it to remain there an hour or more. The powder 
will absorb any greasy or oily substance, and later 
may be shaken out. In using gasoline for cleaning 
in this way, have a generous amount, and allow for 
rinsing the articles well. The gasoline may be used 
more than once, for the dirt which it contains will 
settle to the bottom of the vessel in which it stands 
and the clear liquid may be poured off. Use it out 
of doors, or in a strong outward draft, that the in- 
flammable vapors it produces may blow harmlessly 
away. 

To many people, the word "chemical" always 
means an acid. Now, acids and alkalis differ so much 
in their properties, that it is wise to be able to distin- 
guish between them. Injuries due to the use of one 
may frequently be remedied by prompt use of the 



SOAP MAKING 133 

other. Alkalis are especially useful in laundry work 
because of their action upon grease of most kinds. 
Some of the salts formed with the alkali metals are 
alkaline in reaction. Among these are washing and 
cooking soda. 

HOME SOAP MAKING 

All fats and oils are compounds of certain fatty 
acids combined with glycerine. Glycerine is easily 
separated from this combination by strong alkalis, 
and thus soaps are made. The glycerine is a by-pro- 
duct in many soap factories, but it is not evident in 
home-made soap, being thrown away with any waste 
water, or, perhaps, left in the soft soap. The various 
fats are composed of different kinds of fatty acids, so 
we have varieties of soap made from them. 

Rosin acts like fatty acids, for it is able to combine 
with alkali to make rosin soap. This is good for 
rough work, but it is apt to separate in hot water, 
settingjree the rosin acids, which may settle upon the 
fabric being washed, giving it the odor of rosin or 
causing it to become yellow. It is very objectionable 
when the clothes come to be ironed. This rosin also 
makes fabrics likely to take up dust. If the clothes 
are well rinsed, the amount of rosin soap in ordinary 
yellow soap gives no trouble. 

I have often been asked for a recipe for home-made 
soap, and, too, I have had many students write me of 
their success in this process. Many housekeepers 



134 CHEMISTRY OF THE HOUSEHOLD 

keep and clarify the fats from food. Soap may 
easily be made from this, as follows: 

Take a pound can of lye (Babbitt's potash is good) 
and dissolve it in three pints of cold water. It will 
become quite hot as it dissolves, and care must be 
taken in adding the lye to the water, as it is apt to 
spatter, and is likely to irritate the hands. 

Have ready five pounds of clean fat, which has been 
melted and strained through cheese-cloth to remove 
all specks of brown. When the lye is cool, pour it 
slowly on the grease, stirring it with a stick until the 
two mix, and the liquid' becomes about as thick as 
honey. Too long stirring may cause the ingredients 
to separate. 

Mould the soap in agate or wooden trays. If a 
wooden box is used, it should be lined with several 
thicknesses of wrapping paper. The layer next the 
soap should be oiled. The soap should harden in a 
moderately warm place, and then may be cut into 
cakes. This is the so-called "cold process" soap. It 
will not be suitable for fine work but improves with age. 

Several students have described to me how 
they remembered seeing soap made at home from 
alkali obtained by leaching wood ashes. The ashes 
were put into a large box pierced with holes, the 
box placed over the soap kettle, and hot water was 
poured upon the top. This alkali would make soft 
soap, which would be stored in barrels. If hard soap 
were desired, salt was added to some of the soft soap. 



DISH WASHING 135 

A reaction takes place by which some of the sodium 
in the salt is combined with the fatty acids, sufficient 
hard soap being formed to harden the mass. Nowa- 
days, even when we buy "potash" we are quite sure 
to find that we can make hard soap, for it almost 
always is chiefly soda (caustic soap). 

Washing soda has a great many uses, and I am 
frequently reminded of new ones by our students. 
I am told how excellent it is to put a little in water 
and boil this in the cooking dishes on which food has 
hardened or burned. Another describes how she 
cleans silver by boiling it with a little soda, then rins- 
ing it in very hot water and drying quickly and 
thoroughly. The wife of a dairy farmer assures me 
that she could never get her creamery cans suitably 
clean without plenty of sal soda, which quickly 
removes the butter fat. When we use it in laundry 
work, however, we must remember that, like other 
solids, when it dissolves, a saturated solution forms 
around^each piece, and this strong solution may in- 
jure anything on which the pieces rest. Therefore 
the crystals should always be dissolved, and the solu- 
tion diluted as much as may seem necessary. 

DISH WASHING 

The washing of dishes takes so much time in every 
house that it is evidently a subject calling for close 
attention. Nothing is more desirable than that this 
work be done thoroughly and well ; still, it is doubtless 



136 CHEMISTRY OF THE HOUSEHOLD 

possible to plan for it in such a way that time may 
be saved for other matters. 

In the first place, systematic work is sure to go 
more rapidly than haphazard fashions. The dishes 
should be prepared for washing by scraping them as 
clean as possible, and some housekeepers advocate 
rinsing off many of them under the hot or cold 
water faucets before putting them in the dish- 
pan. Hard water is very unsatisfactory for dish 
washing, and the use of soda or borax is a great help 
when soft water is not available. Borax is not so 
hard on the hands as soda. Dishes which have 
contained milk or eggs are better rinsed well in cool 
water, for heat hardens the albumins so that they are 
removed with difficulty. 

Plenty of hot, soapy water is necessary to do this 
work easily, and a second dishpan of clear, hot water 
in which to rinse the dishes is a great help. Use 
very little soap on gilt china, however. 

There seems to be a great variety of opinion on 
the subject of washing glass. Many housekeepers 
have expressed a preference for washing it in cold 
water rather than in hot. Where the glass is not 
at all greasy, this is very well. Ammonia or soda in 
the water helps to clean the glass and makes it 
lustrous. Glass washed in cold water should be 
allowed to drain almost dry before it is polished. 

One housekeeper has described to me a wire basket 
which she has had made to hold dishes when they 



DISH WASHING 137 

drain, and which is made to fit into her dishpan. 
Fitting the dishes into this, she is able to immerse 
them in hot rinsing water, and then Hft them out 
to dry. She finds the plan an excellent one. 

Another student writes that she has found sifted 
coal ashes a most useful article to use in cleaning 
knives. Another prefers sifted wood ashes. These 
most be very carefully sifted, so that no hard bits be 
left in, which might scratch the articles polished. 

The kitchen dishes are usually the most difficult 
to wash, and one student describes a home-made 
"scrubber" which she declares is very useful. "Take 
a broom apart, a good one, by removing the wire and 
letting the straw loose," she says. "The upper part 
of the straw is then put into boiling water and left 
long enough to soften it. Then the straws are tied 
together in bundles about two inches across, using a 
strong twine. The twine is pulled tight, and sinks 
into the softened straw, and when dry, it does not 
slip. Ar loop is left for hanging the bundle, and the 
straw is left its whole length. These are so long and 
slender they will reach into anything. They are a 
great saving on the hands, and allow the use of much 
hotter water." 

Many of our students recommend the use of soft 
paper in cleaning greasy dishes, kettles, and pans. 
The papers may be burned, thus disposing of much 
grease which would otherwise find its way into the 
kitchen sink drain. 



138 CHEMISTRY OF THE HOUSEHOLD 



LATENT HEAT 



The subject of latent heat, described on page 12, 
has proved very puzzling to many. It is certainly 
a strange idea at first, that heat does anything more 
than make things warm. Still, a moment's considera- 
tion recalls to mind that heat can do many other 
things. Heat causes chemical change, for substances 
are often changed by strong heat. Heat causes most 
substances to expand. If a sealed can of any sub- 
stance is strongly heated, it will probably explode. 
Heat causes liquids to evaporate, and solids to melt. 

If a liquid is placed in an open dish on a source 
of heat, its temperature will rise until it begins to 
boil. After this, it gets no hotter, no matter how 
much heat is applied, unless the liquid is becoming 
more dense as it boils, as would be the case with a 
syrup, for example. The heat it receives is all 
expended in changing the liquid into vapor, or, as we 
say, changing the "state of matter." The particles 
(molecules) are driven farther apart by the heat. A 
cubic inch of water makes a cubic foot of steam. 
The amount of heat necessary to produce the change 
from liquid to gas varies with different substances. 
Water requires a very large amount. Four times as 
much heat is required to change an ounce of water into 
steam as to vaporize the same amount of alcohol. 
If heat is applied rapidly, the liquid will boil rapidly, 
but it does not affect the temperature. The heat 



LA TENT HE A T 1 39 

used in this way is not lost, but is stored up in the 
vapor as latent heat. The steam is no hotter than 
the boiling water, and heat added keeps it from 
becoming liquid. When vapor condenses and changes 
back to liquid, the latent heat is given out, and 
warms surrounding things. In fact, the vapor can- 
not condense unless the latent heat it contains is 
removed, except under pressure. This latent heat 
makes steam an excellent medium for heating build- 
ings, as it contains so much heat and passes through 
pipes rapidly. Not only is the steam itself hot, but 
it carries a vast amount of heat stored up, to be 
liberated in the cooler regions. 

Latent heat is stored up in water, also, and is liber- 
ated when the water becomes ice. This is seldom 
apparent, for far less heat is thus stored in water 
than in steam, and, too, the temperature of freezing 
water is low. The heat given out when water freezes 
is at 32° F, while that given out when steam condenses 
is at ^12° F. Still, a cellar may be several degrees 
warmer if it contains a tank of water which freezes 
than if the water were not there. The temperature 
may keep about 32° F. where otherwise it might 
go to 26° or less. 

A room is cooled in warm weather by sprinkling 
water upon the floor. The evaporation of the water 
takes much heat from the air, storing it in the 



140 CHEMISTRY OF THE HOUSEHOLD 

vapor produced. Britannia and some other metals 
of which pitchers, teapots, etc., are made will melt 
if placed on a hot stove. If, however, they contain 
water, this is not likely to occur, for the water can- 
not be heated above its boiling point, and this is far 
below the melting point of the metal, and keeps the 
temperature of the metal low enough for safety. 
This reminds me of an experiment I once saw where 
candy was actually made in a pasteboard box. The 
syrup never became hot enough to scorch the paper, 
and thus the paper itself was kept fairly cool. 

USE OF THE THERMOMETER 

A kitchen thermometer may be bought of any 
dealer in the better class of kitchen goods. The 
floating dairy thermometers are convenient. One 
to register 212° F, may be obtained from the School 
for 50 cents. A thermometer made to register oven 
temperatures is more expensive, one registering to 
600° F. costing $1.50. Various uses of the ther- 
mometer are described in Principles of Cookery and 
Home Care of the Sick, but there are many times in 
the kitchen when it is of assistance, as in getting the 
right density for syrups in candy making, for syrups 
in preserving, and the right temperatures for raising 
bread, making soups, custards, etc. 

Some uses of the thermometer in the kitchen are 
the following, described in Miss Parloa's "Home 
Economics": 



BREAD MAKING , I4i 

Olive oil is liquid above 75°. If above this tem- 
perature it shows solid specks, making it look cloudy, 
you may be sure it is adulterated with some fat having 
a higher melting point. 

Butter should melt at 94°. If it does not, you may 
know it is adulterated with suet or some other fat 
having a higher melting point. 

BREAD MAKING 

The composition and manufacture of bread are 
subjects which have been given much study. The 
carbon dioxide which serves to lighten the dough 
raised" with yeast is produced at the expense of 
some of the starch of the flour. This starch is 
completely driven from the loaf as carbon dioxide 
gas and alcohol during the baking. The loss is esti- 
mated at about 2 per cent. Attempts have been 
made in large bakeries to save the alcohol, but no 
economical method has bfeen devised. About fifty 
3^ears ago, German chemists in studying the question 
estimated that the food materials lost in twenty- 
four hours, when bread is raised with yeast, was 
sufficient to supply bread to 400,000 people! These 
figures were certainly startling to the thrifty Germans, 
and the possibility of producing the carbon dioxide 
gas in some less extravagant manner was studied 
with considerable care in German laboratories, and 
also at Harvard University in America. Baking 



142 CHEMISTRY OF THE HOUSEHOLD 

powders are the result of these investigations. 
Gluten is not changed chemically by the action of the 
yeast or of the carbon dioxide, but it is physically 
changed — the escape of the gases stretching it out 
into fibres. Gluten, like other proteids, hardens when 
heated. Baking thus makes the porous condition of 
the dough permanent. 

MAKING BAKING POWDER 

Several students have sent me recipes they like 
to use for making baking powder. The claim is 
made that these cost rather less than the kinds that 
can be bought, and also that they are much more 
effective. Here is one: 

yi lb. cream of tartar. 

i^ lb. cooking soda (bicarbonate of soda). 

yi lb. corn starch. 

The best quality of each must be bought. Sift 
them together at least a dozen times, the last time 
into baking powder boxes. Be careful to seal up all 
cracks by pasting over them paper strips. About one 
half as much of this is required as for the average 
powder sold. 

These proportions would probably give a slight 
excess of acid. We might combine 2^ parts of the 
acid salt with one part of soda if our salts are chemi- 
cally pure. The corn starch is added to keep the soda 
and acid salt from forming quite such an intimate 



DISTILLA TION 143 

mixture. The two salts in contact would very 
slowly combine, and the baking powder thus lose its 
strength. 

DISTILLATION 

A few more words might be said on the subject of 
distillation. I am sometimes asked to explain more 
fully the term "destructive distillation." When a 
complex substance like wood or coal is heated some 
of its ingredients are made volatile at the high tem- 
perature, and so escape as gases. The wood itself 
is broken up into simpler substances. It is plain 
that in this process the original substance is lost as 
such, new substances taking its place, and we there- 
fore speak of the process as destructive distillation. 

When water containing various salts or gases in 
solution is heated, the gases will be given off as the 
temperature rises. At the boiling point, the water 
itself will begin to pass off as vapor. The salts will 
not vaporize unless much more strongly heated. If 
the steam be collected and cooled, it will condense to 
form pure water. This in an illustration of simple 
distillation. If a mixture of alcohol and water be 
heated some of the alcohol will vaporize before the 
water. It may in this way be separated from the 
water, and this process is called fractional distilla- 
tion. This is the principle employed in the manu- 
facture of whiskey, etc. 



144 CHEMISTRY' OF THE HOUSEHOLD 

COMPOSITION OF GAS 

The complex nature of coal gas is shown by the 
following table, which represents an average sample: 

Hydro-carbon vapors 0.6 

Heavy hydro-carbons 4.4 

Carbon dioxide 3.4 

Carbon monoxide lo.o 

Methane (CH4) 30.6 

Oxygen 0.3 

Hydrogen 45.9 

Nitrogen 4.8 

100% 

Of these, the hydro-carbons, carbon monoxide, CH4 
and hydrogen are combustible. 

Coals always contain more or less sulphur, \ hich is 
a great trouble to the gas manufacturer. It fre- 
quently happens that some of it gets into the gas. 
If such gas escapes, the sulphur compounds unite 
with the silverware, giving is a coating of dark 
sulphide of silver. If silver tarnishes quickly, it is 
an indication of a leak of gas or sewer gas. It is 
estimated that a ton of coal should yield 10,000 feet 
of gas, 1,400 lbs. of coke (35 bushels), 12 gallons 
of tar, 4 lbs. of ammonia. 

More than six hundred products are obtained from 
the coal tar. The nature and uses of these products 
would form an interesting topic for futher study. 



COMPOSITION OF GAS 145 

The composition of water gas is somewhat as follows : 

Hydro-carbon vapors 1.2 

Heavy hydro-carbons 12.0 

Carbon dioxide ^ 3.0 

Carbon monoxide 28.0 

Oxygen 0.4 

Hydrogen ..; 3i-4 

CH4 (Methane) 20.8 

Nitrogen 3.2 

100% 

Notice that this gas contains less methane and 
hydrogen (which are combustible), and their place 
is taken by carbon monoxide, which, although com- 
bustible, is very poisonous. There is some carbon 
monoxide in ordinary illuminating gas but not nearly 
so much. The water gas has a strong odor from the 
hydro-carbons (crude gasoline) added to make it 
luminous, but comparatively little of it in the air is 
likely to produce very injurious effects upon living 
things, plants and animals alike. It is the most poison- 
ous substance that comes into the house. It is estimat- 
ed, that about fourteen per cent of the gas manu- 
factured escapes into the earth through leaky gas 
mains. In passing through the soil the odorous part 
of water gas may be strained out, so that it becomes 
odorless. Whole families have been poisoned from 
deodorized water gas leaking into the house by way of 



146 CHEMISTRY OF THE HOUSEHOLD 

the cellar. This emphasizes the importance of having 
a perfectly tight cellar, with cemented walls and 
floor, and the importance of ventilating the cellar, for 
the cellar air finds its way to the rooms above. 
Natural gas contains practically no carbon monoxide. 

SPONTANEOUS COMBUSTION 

We often hear of fires apparently "starting them- 
selves." Such cases are due to accumulation of heat 
produced by slow oxidation. If a pile of oily rags, 
cotton waste, etc., be allowed to stand for a time, the 
oily matter vvill begin to combine slowly with oxygen. 
This may occur in the inner part of the heap, and 
the outer layers retain the heat until, perhaps, the 
kindling point of some of the inflammable oils is reach- 
ed, when the whole mass will burst into flame. This is 
much more likely to happen with linseed oil and 
certain other vegetable "drying oils, " as they unite 
readily with oxygen, and so become hard and varnish- 
like. The mineral oils (paraffine oil) do not combine 
with oxygen at ordinary temperatures, and probably 
will not cause spontaneous combustion. Still, all 
oily cloths should be burned or disposed of in some 
safe fashion. 

CONSERVATION OF ENERGY 

An interesting and important principle, ex- 
plained on page 23 of Part I, and again on page no 
of Part III, is Conservatism. This principle has been 
established by countless experiments, but it is not 



CONSER VA TION OF ENERG V 147 

one that the housekeeper can well investigate. It 
is, however, one she must continually bear in mind. 
Matter and energy can never he created or destroyed; 
both may be transformed, and may therefore appear 
in many different ways. The voltaic cell is a simple 
device for transforming chemical energy into elec- 
trical force. The chemical affinity of two substances 
causes them to unite under the right conditions. 
This union results in the liberation of energy, which 
may appear as heat, light, or electricity. When 
coal and oxygen unite, we get both heat and light 
as a result. Chemical union usually produces heat. 

The energy of our bodies we get solely from the 
food we absorb. We should eat such foods as best 
give us the needed energy, and we should learn to 
expend this energy wisely, as we have but a limited 
amount of it. One student wisely comments upon 
this, as follows: 

"In the economic plan of housekeeping, it would 
be well if each one would endeavor to realize that 
she is a part of the machinery of the household, and 
that to be continually on the move is as disastrous 
to the equilibrium of the home as it is to rust, as it 
were, for want of use. A given amount of rest each 
day is a true part of economy. Then, too, in the 
daily regime, there are ways and ways of doing things. 
Always choose the easiest, if it conflicts not with the 
quality of the work done. For example, do not 
stand while paring potatoes, apples, etc. It is just 



148 CHEMISTRY OF THE HOUSEHOLD 

as easy to do this work sitting, and you can then get 
some rest at the same time. Don't worry — to worry 
is a very extravagant thing, for it uses up valuable 
force, and does no good at all." 



BIBLIOGRAPHY 149 

BIBLIOGRAPHY 

Chemistry of Cooking and Cleaning, Richards and Elliott,. 
($1.00, postage 8c.) 

Chemistry of Daily Life, Lassar-Cohn. ^ ($1.50, postage 

IOC.) 

Chemistry of Plant and Animal Life, Snyder. ($1.25, 

postage IOC.) 

Chemistry of Cooking, Williams. ($1.50, postage 12c.) 
Chemistry of Common Life, Johnston. ($2.00, postage 

i6c.) 
Chemistry of Life and Health, C. W. Kimmins. ($1.00, 

postage IOC.) 

First Lessons in Food and Diet, Ellen H. Richards. (30c., 

postage 4c.) 

Laboratory Notes in Household Chemistry, H. T. Vulte 

and G. A. Goodell. 

Laundry Work, Juniata L. Sheppard. (50c., postage 6c.) 
Story of a Lump of Coal, Martin. (35c., postage 4c.) 
Sanitary and Applied Chemistry, Bailey. ($1.40, postage 

I2C.) 

Elements of Chemistry, R. P. Williams. ($1.10, postage 

IOC.) 

An Introduction to General Chemistry, Smith. ($1.25, 
postage I2C.) 

Essentials of Chemical Physiology, Halliburton. ($1.50, 
postage 14c.) 

First Course in Physics, Millikan and Gale. ($1.25, post- 
age 14c.) 

Introduction to Organic Chemistry, Ira Remsen. ($1.20, 
postage I2C.) 

Organic Industrial Chemistry, S. P. Sadtler. ($5.00 
postage 28c.) 



150 CHEMISTRY OF THE HOUSEHOLD 

U. S. GOVERNMENT BULLETINS 

Industrial Alcohol: Sources and Manufacture. Farmers' 
Bulletin No. 268 (free). 

Industrial Alcohol : Uses and Statistics. Farmers' Bulletin 
No. 269 (free). 

Modern Conveniences for the Farm Home. Farmers' Bul- 
letin No. 270 (free). 

Composition of American Food Material. Bulletin No. 28. 
Office of Experiment Station. (Price 5c.) 

Some Forms of Food Adulteration and Simple Methods 
for their Detection. Bulletin No. 100, Bureau of Chemistry. 
(Price IOC.) 

Arsenic in Wall Paper and Fabrics Bulletin No. 86, 
Bureau of Chemistry. (Price 5c.) 

Chemical Composition of Apples and Cider. Bulletin No. 
88, Bureau of Chemistry. (Price 5c.) 

Note. — For the jree bulletins, send to the Department of 
Agriculture, Washington, D. C. ; to obtain the /or sale bulletins, 
send coin or money order to the Superintendent of Documents 
Washington, D. C. 



SUPPLEMENTAL PROGRAM ARRANGED FOR CLASS 

STUDY ON 

CHEMISTRY OF THE HOUSEHOLD 

By Maurice LeBosquet, S. B. 
Director, American School of Home Economics 

As in the study of chemistry and physics so much emphasis 

is placed on laboratory work, the following supplementary 

program is made up chiefly of simple experiments, such as 

may be performed with little or no apparatus. When heat 

is required, it may be supplied by a small gas stove, a one 

burner oil stove, or an alcohol lamp. The lamp of a chafing 

dish might be used. A thermometer will be loaned by the 

School for 6 cents postage, or one may be purchased for 

CO cents. 

MEETING I 

(Study pages 1-29) 
Water 

To show that ordinary water has gases dissolved in tt. 
See experiment on page 2. The gas dissolved in water is 
not exactly of the same composition as air. It usually con- 
tains ^more oxygen and more carbon dioxide than ordinary 
atmospheric air, varying somewhat with the sources of the 
water. This dissolved gas enables fish and other marine 
animals to live. A fish cannot live in water that has lost its 
dissolved air by being boiled. It is drowned just as human 
beings are, because of lack of oxygen. 

Water of Crystallization 

Make crystals as described on page 5. A certain definite 
amount of water is present in the crystals which varies witn 
each substance. Clear crystals are pure or nearly so. The 
"mother Hquor" remaining after the crystals are formed 

151 



152 CHEMISTRY OF THE HOUSEHOLD 

contains most of the impurities; thus crystallization is a 
method of purification. 

The water in the crystals of washing soda may be shown 
by heating some in a tin dish. The crystals will melt and 
on continued heating, steam will be given off. Not all crys- 
tals contain water of crystallization, — for example, common 
salt, cane sugar. 

Boiling Point 

It is almost impossible to convince any "domestic" that 
water boiling furiously is no hotter than when it is just barely 
boiling. It is instructive to prove this with a thermometer. 
Also observe that the "simmering" temperature is very 
nearly the same as the water when boiling, so that cooking 
may be done nearly as rapidly by simmering and with far 
less fuel. 

Latent Heat 

This is a somewhat perplexing phenomenon. We all recog- 
nize that steam is hot, but that it contains a much greater 
supply of heat than hot water is not so easy to realize. The 
following may make this a little clearer: In a small sauce 
pan or dish put about two tablespoonfuls of water. Heat it 
to the boiling point and then continue the boiling until it 
has all boiled away. Note (i) how long it takes to raise the 
water to the boiling point, and (2) how much time is required 
to convert it all into steam. 

To start the boiling, the water is raised from about 6o°F. 
to 212° F., or through 152°. In converting the water into 
steam, there is no rise in temperature, but the heat has 
to be applied for a much longer period. On page 12 is the 
statement that "966 times as much heat is required to change 
a given quantity of water into steam as to raise it one degree 
F. " but the water in this experiment was raised 150°. As 
966 divided by 152 equals 6 (plus), we might expect that it 
would take six times as long to boil the water away as to 



PROGRAM 153 

raise it to the boiling point. Of course no exact results can 
be expected in this experiment, as not all the heat ap- 
plied is absorbed by the water and used in boiling it, but the 
experiment will show that the steam must contain a great 
deal of heat. 

A similar experiment will show the latent heat contained 
in water in reference to ice. If a teaspoonful of ice cold 
water and an amount of snow or ice which when melted 
would make a teaspoonful, each be added to a glass of water 
of the same temperature, it will be found that the pulverized 
ice or snow lowers the temperature much more than the tea- 
spoonful of ice-cold water. That is to say, a great deal more 
heat would have to be added to the "ice and water mixture, " 
to bring it back to the original temperature, than to the "ice 
cold water and water mixture. " 

Oxygen in the Air 

To show that the atmosphere contains a gas which is used 
up in combustion, attach a candle an inch and a half long to 
the bottom of a saucer with some of the melted wax. Pour 
about one-fourth of a glass of water into the dish, light the 
candle and invert the glass (one with straight sides) - over 
the lighted candle. The flame will grow dim and soon be 
extinguished and the water will rise about one-fifth way up 
the glass. This shows a number of things. In burning, 
the carbon of the hydrocarbons of which the candle is made 
unites with the oxygen, making the gas carbon dioxide. 
This takes up the same volume as the oxygen out of which 
it was formed, but the water quickly dissolves the carbon 
dioxide and the pressure of the atmosphere on the water 
outside the glass forces it up into the partial vacuum formed. 

The nitrogen of the air remains, but this will not "svipport 
combustion," and so the candle is extinguished. 

Manufacturing Water 

That the burning of a candle produces water as well as 



154 CHEMISTRY OF THE HOUSEHOLD 

carbon dioxide may be shown by placing the flame against 
a window pane. A film of moisture may be seen, also, when 
a lamp having a cold chimney is first lighted. The burning 
of a match will show water when it is placed against a cold 
surface, but this experiment is not so conclusive, for the 
wood may contain moisture. The candle contains no moist- 
ure, so the water must have been manufactured by the 
burning. 

Atmospheric Pressure 

We have had one example of the result of atmospheric 
pressure in the candle experiment. The working of a siphon 
i-s an interesting example. Take a small rubber tube, fill it 
with water, pinch both ends, put one end in a glass of water, 
and lower the other end into an empty glass at a foot lower 
level; release the pressure of the fingers, and the water will 
run from the tube, apparently going "up hill" over the edge 
of the glass. The explanation may be found in any text 
book on physics. This is a good way to empty wash tubs, 
etc., using a piece of rubber hose. 

Carbon Dioxide 

Light a splinter of wood and let it burn in a wide-mouthed 
bottle until it is extinguished. Add a tablespoonful of clear 
lime water (obtained at any drug store, or add a small lump 
of lime to warm water in a fruit jar, stir well, cover and let 
settle over night) , close the bottle and shake the lime water 
around. It will grow milky from the formation of carbonate 
of lime (calcium), with which we are more familiar in the 
forms of chalk, marble, and clam shells. 

Again with any sort of a tube (a straw), blow into a little 
clear lime water. It will grow milky, showing that the 
breath contains carbon dioxide. If you will continue to 
blow into the lime water for a long time, the milkiness 
will be seen to disappear. This is because the carbonate of 
lime is dissolved by the excess of carbon dioxide in the water, 



PROGRAM 155 

after the lime water (hydrate of lime) is all changed into 
carbonate of lime. This point comes up in connection with 
hard water and laundry work. 

Flash Point of Kerosene 

The flash point of a sample of kerosene may be determined 
approximately by placing about two teaspoonfuls in a cup, 
then adding hot water to a bowl of water in which the cup 
containing the oil is placed. Stir the kerosene with a ther- 
mometer, and apply a lighted taper to the surface of the oil 
from time to time as the temperature of the oil rises. A 
quick flash over the surface of the kerosene will show the 
flash point. Read the temperature indicated by the ther- 
mometer. 

References: Chemistry of Daily Life, by Lassar-Conn. Chapter 
I, Atmosphere, Combustion. ($1.50, postage 

I2C.) 

Story of a Lump of Coal, by Martin. (35c., 

postage 6c.) 
Air and Water as Food, in Plain Words about 

Food, by Ellen H. Richards. ($1.00, postage 

IOC.) 

Sanitary and Applied Chemistry, by Bailey, 
Chapter on The Atmosphere, Fuels. ($1.40 
postage I2C.) 

Topics: The Formation of Coal — See any good encyclo- 

pedia and geologies. 
Fire Worship — See "Popular Science Monthly," 
Volume X, page 17, also "Public Opinion," 
Volume XIV, page 251. 



156 CHEMISTRY OF THE HOUSEHOLD 

MEETING II 

(Study pages 29-55) 

If the Food Course is being taken, some of the experiments 
here suggested might better be postponed until the lessons 
on Principles of Cookery or Food and Dietetics. 

Starch 

The blue color produced by a tincture of iodine (obtained 
at the drug store) on the faintest trace of starch is a very 
delicate test for starch. Cooked starch shows the test much 
better than uncooked. Note that the blue color is destroyed 
by heat, but appears again when the test is cool. Test 
various foods — grains, vegetables, fruits, and nuts for 
starch. 

The conversion of starch into dextrin may be shown by 
heating a little flour or corn starch in a hot oven for half an 
hour or so, or until it becomes a deep yellow color. Dis- 
solve in a little cold water, filter out the unchanged starch 
by pouring through absorbent cotton in a funnel; test the 
filtered liquid to see if there is still any unchanged starch in it. 
Add double the quantity of alcohol to a part of the liquid. 
The dextrin will be precipitated, i. e., thrown out of solution 
and will settle as a fine powder, because dextrin is not soluble 
in alcohol. The water solution should be concentrated by 
boiling if much is used. 

That the starch is changed by heating with butter or other 
fat may be shown by adding two teaspoonfuls of flour to 
one teaspoonful of very hot butter, stirring for some time. 
Remove a drop on a piece of white paper and test it with 
tincture of iodine. 

Make starch paste by mixing a quarter of a teaspoonful of 
laundry or corn starch with a spoonful of water and adding 
it to a cup of boiling water and boil. To about half a glass 
of this when it has cooled to body temperature (100° F) add 
a half teaspoonful of saliva. Keep the mixture warm (not 



PROGRAM 157 

hot) for some time by placing it in warm water. From 
time to time test small portions with iodine solution as it 
grows clearer. Add saliva to a portion of hot starch; to a 
cold portion testing as before. 

Gluten 

May be the gluten separates from flour as described on 
page 49, or better as described in "Food and Dietetics" page 
41. Bake part of it in an oven. 

Experiments with other proteids also described on pages 
41 and 43 of "Food and Dietetics." 

Experiments with yeast described on page 45 of "House- 
hold Bacteriology, " Part I. 

"Digestion is Synonymous with Solution" 

This statement is made on page 35. To show the relation 
of the length of time required to make a solution, take two 
equal portions of any crystals, such as washing soda or alum, 
and pulverize one portion. Stir each in a glass of water and 
observe the time for each in dissolving. Note that the time 
required for complete solution is determined by the largest 
crystal. 

This experiment shows how important a part of digestion 
chewing is and that the teeth are primarily digestive organs. 

Cooking Meat 

See experiment on pages 50 and 51. 

Mineral Matter — Gelatin 

See experiments on page 53. 

References: Chemistry of Cookery, by Mattieu Williams 
Pages 19-31. Albumen. ($1.50, postage i6c.) 
Chemistry of Daily Life, by Lassar-Conn. Pages 
56-66. Digestion of Food. ($1.50, postage loc.) 

(Select and send to the School a composite set of answers 
to Test Questions on Part I, and report on supplemental 
work and experiments.) 



158 CHEMISTRY OF THE HOUSEHOLD 

MEETING III 

(Study pages 55-65) 

Cleaning: Acids, Alkalies, and Salts 

Strips of litmus paper may be obtained at a drug store or 
will be sent from the School on request. Moisten the blue 
paper in vinegar, lemon juice, tomato, solution of cream of 
tartar, etc., and then in ammonia (even the vapor will 
change it), in solution of washing soda, baking soda, borax, 
soap, and various washing powders. If the paper is washed 
in running water after being turned blue with ammonia, a 
test for acid may usually be found in milk, molasses, and 
sometimes butter. One piece of paper will be found to turn 
from blue to red and back again to blue an indefinite number 
of times when wet with solutions of acids and alkalies alter- 
nately. 

Buy five cents' worth of hydrochloric acid and a little 
caustic soda at the druggist's. As caustic soda is unpleasant 
to handle, it is best to have the druggist dissolve it in water. 
Now pour a part of the acid into a saucer or glass, with a 
little water, and add the solution of caustic soda until the 
mixture begins to turn the litmus faintly blue. In an agate- 
ware dish, free from worn places, evaporate the solution to 
dryness. A whitish substance will be found, which by test- 
ing will be recognized as common salt. 

From two very active chemical substances has been 
formed a neutral substance — salt. Not all salts, however, 
are neutral. Sodium carbonate (washing soda) is chem- 
ically a salt, but it is made up of a very strong alkali forming 
element — sodium — and a very weak acid — carbonic acid — 
and the alkali properties predominate. Cream of tartar is 
an example of an acid salt. It is acid potassium tartrate, 
which is a double salt, that is, tartaric acid is added to neutral 
potassium tartrate, the result being a substance which has 
acid properties. Common alum is slightly acid to litmus paper. 



PROGRAM 159 

Soap 

Soap chemically considered is a salt, made up of a fat 
acid and the metallic substance sodium. The fatty acid 
can be separated by adding any acid like vinegar to a solu- 
tion of soap. If the solution is warm, it rises as a scum 
to the top. It can be dissolved in ammonia, forming an 
ammonia soap. The sodium part of the soap unites with 
the acid and forms a salt. If hydrochloric acid is added to 
a soap solution (a sufficient quantity to make the solution 
very slightly acid), the fatty acid removed, and the residue 
evaporated to dryness, common salt will be found. 

If lime water be added to a solution of soap, white clots 
of "lime soap" will be formed which are insoluble in water, 
but on collecting and drying will be found to dissolve in 
gasoline, naphtha, or kerosene. This is why naphtha or 
gasoline is useful in cleaning bath tubs, bowls, etc. Quite 
a good varnish can be made of aluminum soap, made from 
alum and white soap, dried and dissolved in gasoline. 

Washing Powders 

It is not difficult to get some idea of the composition of 
the various washing powders on the market. When acid 
is added to a solution, if there is effervescence, washing soda 
is probably present. A skum would indicate that soap 
formed a part of the mixture. 

Hard Water 

In the experiment with cabon dioxide it was shown how 
carbonate of lime might be dissolved by an excess of carbon 
dioxide gas, the bicarbonate of lime being formed, which is 
soluble in water. This is an example of an "unstable" 
chemical compound. Simply boiling drives ofif the excess 
of carbon dioxide gas, leaving the ordinary carbonate of lime 
which is insoluble and is deposited on the sides of the tea 
kettle or other vessel. This may be shown by blowing into 
lirne water until the cloudiness whiqh ^t f;rst appears begin§ 



i6o CHEMISTRY OF THE HOUSEHOLD 

to dissolve. As it is difficult to dissolve it completely, the 
solution may be filtered. On boiling the clear solution, the 
milkiness will appear again. 

Hardness that is brought about by the sulphate of lime — 
"permanent hardness " — is difficult to remedy by any house- 
hold means. Washing soda helps a little, but not very 
much. The so-called alkali waters of the west, in addition 
to sulphate of lime contain sulphate of soda and other salts, 
so that they are beyond remedy. 

Reference: Chemistry of Daily Life — The Manufacture of 
Soda. Page 194. 



MEETING IV 

(Study pages 66-88) 
Laundry Work 

Bluing May Yellow Clothes: On page 70 is the statement 
that the repeated use of ordinary bluing may stain the clothes 
yellow. To prove this, dip a piece of white muslin into a 
strong bluing solution — about a teaspoonful of liquid blu- 
ing to a cup of water — dry the cloth with a hot iron and boil 
it in a little strong soap solution. The color will be seen to 
fade. Rinse and dry with the iron. On comparing the 
cloth with part of the original piece, a slight yellow stain 
will be seen. This is oxide of iron (iron rust) and can be 
proved to be such by adding a drop of pure dilute hydro- 
chloric acid and then a drop of yellow prussiate of potash 
(potassium f erro-cyanide) , the intense blue color produced 
being a test for iron. The conditions in this experiment 
are, of course, much more severe than obtained in ordinary 
washing, as most of the bluing is washed out before the 
clothes are boiled again, but the experiment proves the pos- 
sibility. As indigo costs about a dollar a pound and Pru3- 
sian blue only a few cents, practically all the bluings on ths 
market are Prussian blue. 



PROGRAM i6i 

Iron Rust Stains 

Make "rusty water" by letting a few nails stand in a can 
of water over night or longer. Boil some white cotton cloth 
^n a little of the water. Try the same with wool. Strain 
some of the wate r through white muslin and boil the muslin 
in soapy water. 

Stains 

One of the classes gave a demonstration before a large 
audience on the removal of stains as outlined in this lesson. 
As the only way to learn how to remove stains is to remove 
stains, it would be advisable to make a few, if none are at 
hand, and then try the experiments on them. 

Referenees: Chemistry of Daily Life — Inks. Page 178. 

Laundry Work, by Juniata L. Sheppard. (50c., 
postage 6c.) 
(Send answers to Test Questions on Part II, and report 
on supplemental work.) 

MEETING V 

(Study pages 89-1 11) 
Baking Powder 

Perform experiments suggested on pages 90 and 91. 

Reference: Baking Powders. Bulletin No. 119, Maine Agri- 
cultural Experiment Station. (Loaned for 2c.) 
Lighting 

(i) See Experiment page 93. 
(2) Insert the small end of a clay pipe stem in the inner 

part of a candle flame and touch a lighted match to the 

other and so prove that the candle is a "gas factory. " 
3) With a piece of wire gauze make the experiments 

illustrated on page 95. 
(4) Visit the local gas plant if there is one — or the electric 

light station — obtaining perrnission first from the ofl&ce. 



l62 CHEMISTRY OF THE HOUSEHOLD 

Electric Batteries 

(i) Detach one of the batteries that furnish the current 
for the electric bell, attach a wire to each pole and place 
the other ends on the tongue and note that the electric 
current gives a slight "taste" — i. e., stimulates some of 
the nerves of taste. 

(2) Get some one to explain the action in an electric bell 
or send 2c. stamp to the School for circular giving descrip- 
tive diagram, diagrams for bell wiring, etc. 

Plants 

Examine with a microscope the "breathing pores" on the 
under surface of leaves. 



MEETING VI 

(Study pages 111-122) 

Chemical Formulas 

Reference: "Chemistry of Cooking and Cleaning," by Rich- 
ards and Elliott. Pages 9-30. ($1.00, postage 

IOC.) 

' ' Elementary Chemistry. " Text book of Ameri- 
can School of Correspondence. (Postage 4c.) 

Housekeepers' Laboratory 

Make some of the tests described. 

Reference: "Some Forms of Food Adulteration and Simple 
Methods for their Detection. " Bulletin No. 
100, Bureau of Chemistry, U. S. Department 
of Agriculture. Send loc. (coin) to the Supt 
of Documents, Washington, D. C. 

(Send answers to Test Questions on Part III and report on 
supplemental work.) 



INDEX 



Absorbents of grease, 74 
Acetylene gas, 99 

generators, 100 
Acid, definition of, 56 

test for, 56, 116 
Air, 14, 153, 

as food, 30 

composition of, 16, 22 

pressure, 15 

properties of, 14 
Albumin, 46, 48 
Alkali, 56, 71, 117 

metals, 58 
Alkalies, effect on paint, 84 
Alum, 120 
Ammonia, 58, 120 

use of, 71, no 
Aniline, 98 
Anthracite coal, 25 
Argon, 20 
Atmosphere, 14, 20 
Atmospheric pressure, 15, 154 
Atoms, 112 

Baking powder, 89, 142, 161 

chemistry of, 89 
Batteries', 107 
Bibliography, 149 
Bituminous coal, 25 
Bleaching, 80 

powder, 80 
Blue flame oil stoves, 27 



Bluing, 131 

clothes, 69 
Bluing stains, 74 
Boiling clothes, 69 

point, II, 152 
Boneblack, 24 
Borax, 62, 71, 117 

use of, 71 
Bread, 38 

digestibility of, 42 

flavors of, 41 

ideal, 39 

kinds of, 38 

making, 40, 141 
Broth, 50 
Brushing woolens, 7 1 

Cafifein, 47 

Candle flame, chemistry of, 92 

Cane sugar, 32 

Carbohydrates, 30 

Carbon, 17 

dioxide, 18, 154 

monoxide, 21 
Carbonates, test for, 119 
Casein, 46, 49 
Caustic potash, 58 

soda, 58 
Cell, dry, 108 

Leclanche, 106 

voltaic, 105 
Cells in series, 107 

163 



1 64 



CHEMISTRY OF THE HOUSEHOLD 



Cellulose, 31, 34 
Cement, 104 

hydraulic, 104 

Portland, 104 
Charcoal, 23 

manufacture of, 23 

use of, 24 
Chemical signs, 112 

terms, 1 1 1 
Chemical, care of, 116 

closet for, 118 

household, 1 15 
Chemistry of a match, 21 

of baking powder, 89 

of bread making, 40 

of laundry, 66 

of candle, 92 
Chill, cause of, 19 , 
Chloride of lime, 81 
Chlorides, test for, 120 
Chlorine, action of, 81 
Chlorophyl, 109 
Cleaning, 55-88, 157 

metals, 85 

porcelain, 86 

with gasoline, 132 

woodwork, 84 
Coal, 24 

anthracite, 25 

bituminous, 25 

distillation of, 97 

gas, 97, 114 

tar products, 98 
Coffee stains, 75 
Coke, 25 



Coking coal, 25 
Collagen, 47 
Combustion, 20-29 

in body, 30 

spontaneous, 146 
Comparison, testing by, 115 
Composition of air, 16, 22 

of fats, 44 

of soap, 59 

of sugar, 32 

of water, 8 
Compounds, 6 

chemical, 57 

washing, 61 
Conservation of energy, no, 146 

of matter, 23 

principle of, no 
Cooking, 37 

effects of, 5 1 

object of, 51 

of fats, 43 

soda, 89 
Cotton fibres, structure of, 66 
Cream of tartar, 91 
Crystals, shape of, 6 

water in, 151 

Decay, 54 

cause of, 54 
Destructive distillation, 143 
Dew point, 19 
Digestion of fats, 43 

of proteids, 5 1 

of starch, 35, 37 
Disinfection, 83 



INDEX 



165 



Dish washing, 64, 135 
washing machines, 65 

Distillation 2, 97, 143 
destructive, 143 
fractional, 143 

Distilled water, 2 



Electric batteries, 162 
Electricity. 105 
Elements, 22 

definition of, 22 

table of, 112 
Emulsions, 59 
Energy, 45 

conservation of, no, 146 

source of, 45 
Experiments, value of, 113 
Explosions, 94 

cause of, 94 
Explosive mixtures, 94 
Extractives, 47 

Fats, 43^, 57 

composition of, 44 

cooking of, 43 

digestion of, 43 

heat from, 45 
Ferments, 36 
Fertilizers, 109 
Fibres, 66 

chemical action on, 67 

cotton, 66 

linen, 66 

Silk, 67 



Fibres, structure of, 66 

wool, 66 
Filtering, 7 
Fire test, 28 
Flash point, 28 
Flavor, 53 
Food, 29 

air as, 30 

nitrogenous, 45 

use of, 29 
Freezing, 13 

latent heat of, 13 
Fruit, 31 

food value of , 3 1 

stains, 75 
Fuel value, 28 
Fuels, 28 

comparison of, 28 

Gas, 97 

acetylene, 99 

coal, 97 

composition of, 144 

from candle, 92 

gasoline, 10 r 

natural, 99 

water, 98 
Gasoline, 27 

cleaning with, 132 
Gelatinoids, 46 
Glucose, 32 
Gluten, 46, 49, 156 
Grape sugar, 33 
Graphite, 24 
Grease spots, 73 



166 



CHEMISTRY OF THE HOUSEHOLD 



Hard water, 7, 62, 159 

water, cooking with, 63 

water with soap, 63 
Heat, 12 

latent, 12, 138, 152 
Home soap making, 133 
Household chemicals, 115 
Housekeeper's laboratory, 113 
Hydro-carbons, 25 
Hydrogen, 9 

peroxide, 84 
Hydraulic cement, 104 

Impurities in water, 127 
Ink, 77 

colored, 78 

indelible, 76 

on carpets, 78 

removal of, 77 
Iron rust, 78, 160 



Lamps, kerosene, 96 

safety, 96 
Latent heat, 12, 138, 152 
Laundry, 66, 127 

chemistry of, 66 

work, 127, 160 
Lead pipes, 7 
Leaven, 39 
Leclanche cell, 106 
Legumin, 46 
Levulose, 33 
Lighting, 92 
Lime, 102 

quick, 103 

slaked, 103 

soap, 63 

test, 120 

water, 103 
Linen fibres, structure of, 66 
Litmus, 56 



Javelle water, 82 

Kerosene, 26 

flash point of, 155 

lamps, 96 

use in cleaning, 85 

washing with, 131 
Kindling point, 20 

Laboratory, 116 
acids for, 116 
housekeepers, 113 

Lactose, 32 

Lamps, 9O 



Maltose, t^t^ 

Match, chemistry of a, 21 
Matter, conservation of, 23 
Meat, 49 

efifect of temperature on, 5c 
Mercerization, 68 
Mildew, 75 
Milk sugar, 33 
Mineral matter, 52 
Molecules, iii, 113 
Molasses, 32 
Mortar, 104 

Natural gas, 9(^ 



INDEX 



167 



Nitrogen, 16 

for plants, no 

properties of, 16 

use of, 45 
Nitrogenous foods, 45 

foods, cooking of, 48 

Oil stoves, blue flame, 27 

Oils, 57 

Oxide of calcium, 102 

Oxides, II 

Oxygen, 10 

in air, 153 

properties of, 10 

Paraffin, 26 

in washing, 130 
Paint, removal of, 76 
Peat, 25 
Peptones, 51 

Peroxide of hydrogen, 84 
Petroleum, 26 

crude, 26 
Phosphates, 1 20 
Plant fertilizers, 109 

foods, 108 
Plants, 108 

house, 108 
Plaster, 104 
Potash, 58 

caustic, 58 
Pressure of air, 15, 154 
Program for supplemental 

151 
Proteids, 46 



Proteids, digestion of, 51 
Ptyalin, 36 
Pump, 15 

force, 16 

suction, 17 

Quick lime, 103 

Rain wat^r, 4 
Rinsing clothes, 69 
Rochelle salt, 91 
Rosin soap, 133 
Rust, iron, 78, 160 

Saleratus, 89 
Salt, a, 57, 158 

common, 52 

Rochelle, 91 
Safety lamps, 96 
Saturated solution, 5 
Silver polish, 87, 121 

sulphide, 86 
Smoke, 26 

nature of, 94 
Soaking clothes, 68 
Soap, 57, 158 

action of, 59 

composition of, 59 

kinds of, 60 

lime, 63 

making, 132 

rosin, 133 
study, solution, 71 

with hard water, 63 
Soda, 89 



i68 



CHEMISTRY OF THE HOUSEHOLD 



Soda, ash, 6i 

caustic, 58 

cooking, 89 

washing, 61 
Softening water, 62, 129 
SokibiUty of water, 5 
Solution, saturated, 5 
Solvents, 118 
Soup, 50 

Spontaneous combustion, 146 
Stains, 70 

bluing, 74 

coffee, 75 

fruit, 75 

removal of, 73 

vaseline, 75 
Starch, 33, 121 

changed to sugar, 35 

conversion of, 35 

cooking of, 37 

digestion of, 35, 37 

source of, 34 

uncooked, 72 
Starching clothes, 72 
vStill, a, 4 
Sucrose, 32 
Sugar, 32 

brown, 32 

cane, 32 

digestion of, 35 

fruit, 33 

grape, iz 

maple, 32 

milk, 33 

starch, 33 



Sulphur candle, 83 

dioxide, 82 
Sulphurous acid gas, 117 

Table of common substances with 

formulas, 114 

of elements, 112 
Tannic acid, 47 
Tarnish, 86 
Temperature of boiling point, 12 

vital, 30 
Tests, 119 

sample, 122 
Testing by comparison, 115 

colors, 113 
Thein, 47 
Thermometer, 12 

use of, 140 

Vapor, water, iS 
Varnish stains, 76 
Vaseline, 26 

stains, 75 
Ventilation, 15 

of sleeping rooms, 18 
Vital temperature, 30 
Voltaic cell, 105 

Water, 1-14, 127, 151 

as temperature regulator, 13 
boiling point of, 1 1 
bread, 41 
composition of, 8 
distilled, 2 



INDEX 



169 



Water, effect of freezing, 13 
effect of heating, 1 1 
effect on lead, 7 
effect on metals, 6 
filtered, 7 
gas, 98, 145 
hard, 7, 62, 128, 159 
heat, absorption of, 13 
impurities in, 127 
lime, 103 

manufacturing, 153 
natural, 2 

of crystallization, 151 
permanent hardness, 62 



Water, rain, 4 

softening, 28 

solubility of, 5 
Water vapor, 18 
Washing colored goods, 70 

powders, 121, 159 

soda, 61 

soda, use of, 135 

woolens, 70 
Whitewash, 105 
Whiting, 87 
Wool fibers, structure of, 66 

Yeast, 39 



